totally know how you feel. i had three at the same time and they didnt go away for about 2 months! tried everything, but the best thing is to just wait- i found that burning them and picking them made it feel much better, but it would only come back the next day twice the size and 5 times more painful!
i found that custard powder really helped though, just get a pinch of it and place it on the ulcer- u wont feel any burning sensation or anything but it really soothes it.