Just curious why are you not seeing rheumatologist for your liver problem? and you can take pain killers some work completely off your kidneys and others the liver. You need to use ones that work off being cleaned out by your kidneys.
My husband has hemochromatosis which is too much iron in your blood...but you have elevated liver enzymes and other liver problems. Like lupus it can attack any major organs in your body and can be missed by many doctors from what I am reading on support group posts..sites for it like this one for lupus. I would get tested and you might eventually needed liver biopsy .my husband did and most all people on support site seem to also have one. It is not pleasant so ask to be put into twilight zone. It does run in families...it is genetic. My husband's siblings all got tested and not one other did have it which is unusual.
I personally think you should try to go since this is very important to your bf. I know you need to put your body first....and there are some things you can do so at the wedding you can do just that. Like if reception is being held in nice hotel book room in same hotel so you can go up and rest. If not book a room in hotels as close to reception as possible so you can go and rest as you need too.
Sure you bf will do all the driving....plan on time to stop every hour and let you get out and walk and stretch your legs....drink fluids during the entire drive...yes you will need to stop to go the bathroom but that is good since you can let your legs stretch and move.
I had this same situation last summer with my niece's wedding who means a lot to me. They also did somethings like made sure there was parking near the wedding so neither of us..since my husband's ankles are destroyed from the disease. We did bring chairs since sitting was said to be limited and i did not want to keep bothering them as weddings are stressful....but they had chairs reserved for us as well and in shade. If it out doors...i have some very large nice straw hats with 6 inch brims so my entire face is covered as well as shoulders. I get this sunscreen that has zinc oxide in it so it is thick and takes about half hour to soak in...but it has stopped rashes even in car..where i tend to get worse ones. Isabella catalog carries excellent sun protection that they try on themselves before offering . but sure you have sun block that already works by now for you.
I would add good extra hour to drive or half hour so you can drink fluids all the way down plus stop about every hour to go bathroom plus stretch your legs. Do not starve yourself either try to stick to your normal eating times so your body stays on as normal schedule as possible. You can nibble at reception if it has full meal and you are not that hungry at that time.
Do not drink alcohol...i save small portion of champagne for toast if i am feeling okay if not i do not.
But at my niece's wedding....wedding was nice...but where they had reception was normally a wine tasting room...large room. Friends have winery and let them have use of it to be married in garden area than reception in this large room. It was extremely noisy and my poor mom could not hear me even across table and i had hard time to hear her. Noise like many of us have said just really made me start to feel sick....and i noticed with all these people they had only two bathrooms...if i get sick one is going to tied up with me until i can get well enough to get home to even my parents house or friends. So I did end up having to leave after the meal because it was just too much noise plus...but if yours in a place with room upstairs than i would have just gone up there....and rested a bit with my husband than come back down.
Plus if you spend the night and ask for room not at end of hall but in middle will be quieter since you do not hear fire door slamming shut or opening all night...you should be okay i would think.
Bring all your meds plus any extra that you might take if you do get sick. I just have bag that all of them go into....but just make sure you have place to go rest if you need during the reception time. Make sure your bf will fine with you needing to rest during it and he might be left alone...but since it is his family he should be okay.
I have found main key to keep drinking fluids, water, juices all day and resting as i need too. Even if i go on plane....i get more drinks than they offer and yes you have to get up and go bathroom but walking is good for us as i get stiffen up once i sit more half hour...there are those compression socks but if you do stop every hour to walk a bit etc...than you should be just fine.
I hope you try and go...as it does mean a lot to your bf. They give ups so much for us due to our diseases that i try hard to go when it means a lot. Also...if you feel stressed etc....your doctor might you one or two low dose as possible of of lorazepam it is weak version of Xanax and help you relax or sleep on way down even.
GOOD luck on going...also i hope you are off pred pills and hope you are getting regular bone scans by now since sounds like you have been on it off and on for while. Pred pills can do more damage to your kidneys than any otc is going to do to your liver...so you should check out serious side effects of it...plus my brother at age 30 had bones of someone in late 60's due to pred pills..i also was getting weaken so i stopped letting them prescribe it unless in very serious situations..life /death kind. There are other drugs...also your body can stop producing it so you should also have test...takes almost all day by endocrinologist to make sure you are still producing it.
Making your face get the 'moon' is nothing compared to all the damage it can do internally to your body ...so please be cautious using pred pills...and see specialist for your liver problem to get to the bottom..i hope you do have good time at the wedding!