The way I handled it is I think of "Is this a valid concern?" and "Can I do anything about it?"
Using your acne as an example, "is this a valid concern for this person to have to be worried about my acne?" and the answer is probably no. It doesn't effect them and it's not like they're worried for your health. So you can disregard it if you like to. "Is this a valid concern for me to be worried about my acne?" - If you're not concerned about the acne, then you can disregard it. If you are concerned about it, then instead of viewing it as a negative thing, try to view it as an external validation for something you want to change. "I guess I have noticed my acne is getting worse, I guess I could get a cleanser of some kind" or something.
Feeling bad to feel bad doesn't solve anything. You either disregard it or you turn it into something helpful.