I had a bump at my chin 3 months it bursted and all the puss, blood were out but now I feel that there is something left inside can feel it too?

Neck infection. What you are describing is an abscess with a collection of pus that erupted and drained. There are several kinds of things in the neck that can do that. A common one is a lymph node. Less common are cysts. Even though the infection has been drained, there is often some surrounding swelling and firm character of the tissues that always occurs. It could take several weeks for that to go down.