My son 2 year old having acne issues from past month, at every two days he is having new acne on his face and sometimes on his hand and arms, no rashes and no red skin, what is the reason for it?

Wouldn't be acne. Your 2 yo can easily have bumps on his face triggered by illness, reaction to food or something that came in contact. They do not get acne. Without seeing this and reviewing the kids history little can be offered as a reason. If it persists have it looked at.