A: In this case you are allowed to resort to treatment to cover the scars and the marks. This type of cosmetic is allowed. The haraam cosmetic is that which is done to alter or change the natural and normal way one looks. Acne is an illness and the marks it leaves is not something natural or normal. You are therefore, permitted to use substances to cover these marks.
Q: Are you allowed to put foundation on your face to cover you blemishes or is this part of makeup and shouldn't be worn in front of non mahrems? I've got marks/scars on my face because of the acne I used to have.