Does appling moistrizer bad for oily skin?

No.: Not "bad" for it, but could make it more oily unless you use a water-based or oil-free moisturizer.

Oily=not dry: If your skin is already oily, that means it is not dry and thus should not need moisturizer use. In any case, moisturizer application should not harm you/your skin, but unless using on face and some lotion can make acne worse. Otherwise, lather-on if you feel the need to do so. If you have trouble, consult doc. Good luck.