Hi--any chance of posting a photo on this page or at imageshack or photobucket and giving me the link?
OK, while these could be the canker sores of herpes type 1 (not genital herpes) you may have a disorder called Behcet's disease which is a type of autoimmune disorder. Is is treatable with predisone and immune modulating medications, and I would send you to a rheumatologist if a herpes screen was negative. Here's an informative link for you.
OK--I still wouldn't rule out Behcet's. Another autoimmune disorder that this could be would be lupus. These could be canker sores and there may be a problem with a vitamin deficiency. Finally, although not very likely, this could be a sign of your being HIV positive. I would check an antinuclear antibody, rheumatoid factor, sed rate, C reactive protein, and an HIV screen. Finally this could be an infection like cryptococcus or blastomycosis. You'd need blood work and cultures to see which of these could be the possible cause. If this answer still doesn't satisfy you enough to give me at least a Good Service rating, please just ask me for any more information you need.