My son is 21 years old and has bright red patches near his gum line in his mouth on both sides, one side worse than the other. This is not tooth or gum decay at all nor is it gingivitis or anything like that. He has excellent dental health was seen prior by a dentist and has no cavities and had a teeth cleening. He doesn t feel pain and didn t even know it was there until I noticed it. It appears as a long, very bright red patch near his gums. He does not smoke or drink and is basically a health guru who eats only organic foods etc. He has also only had one girlfriend since the age of 16. What could cause this?