The most likely cause of hair loss in a 24 year old man is heredity ("male pattern hair loss" is the usual term. Stress,
sweatingSweating
Sweating - absent, flushing, and acne more than likely have nothing to do with it.
My advice to you is to consult a dermatologist about all these problems. Your options for hair treatment include minoxidil (over-the-counter) and Propecia, which does a nice job of holding onto the hair you have, but you need to take a pill indefinitely and insurance doesn't pay for it. Worth exploting, in any case.
The other problems are easily dealt with, and worth a visit.
Best.
Dr. Rockoff