I used topical treatments on my acne and some of the blind pimples left a bump as if the head is still underneath. i believe its not scar as i din't pop it. can i know if it will go away on its own or is there somthing i should do to get rid of it ?

Manage it: Listen friend. Most of what you read / hear about acne is not true. You'll scar from a bad pimple whether or not it pops. If it's this severe, you need to prevent new pimples from forming -- you can do nothing about what's happened. Keep loading on the topical benzoyl peroxide and/or retinoic acid and get with your physician to add some prescription Rx for a few months. Best wishes.