Hi!
Excessive
stress generally doesn't cause these kinds of symptoms. Generally there could me multiple reasons for a white tongue and
acne over chest. Especially when
HIV is negative, you shouldn't worry much and should
consult a dermatologist. Now that you have stated that you are under lot of stress, you should know how to control your stress and in case it is difficult for you, you shouldn't mind getting some psychological help from specialists.
Hope I am able to solve your concerns.
Have a nice day!