I had a corneal ulcer last year and unfortunately it was the end of my contact wearing! It happened out of the blue - one day while I was driving I suddenly felt like something was in my eye and burning and I had to rip out my contact lense and drive straight home (with one eye open!)
I had been wearing contacts for about 12 years without a problem ever. I was bad, though, and I wore them 24/7 for two weeks, wore my glasses for a day, then right back to the 24/7 contacts (disposables). I knew I shouldn't be doing that but my eyes always looked great when I got them checked.
When I got the ulcer my doctor told me not to wear the contacts while I administered medication (drops) for a week (I think). After that he checked and said that there was no residual damage and I could go back to contacts, but I had to be good and remove them at night. I tried and for some reason the contacts just don't seem to work for me anymore - we tried a few different ones and the doctor swears that it the right prescription but I just don't feel right with them in my eyes any more and that drives me crazy! I hate wearing my glasses. I want to go back to contacts but I don't know if I'll be able to, so I'm now hoping to be able to afford the laser surgery in a couple of years.
This probably didn't help you and I apologize, but this was my experience with it...best of luck to you.