I've had a lump on a decaying tooth for 3 months it was soft at first but harden, it drains small amounts of puss. , can it be a abscess? i'm 21yr

Yes: Sounds like a worsening infection. Get to the dentist right away to have this examined and treated. You are putting yourself in greater danger by waiting. Good luck.

See a dentist: A tooth abscess won't go away without treatment and the infection may spread to your jaw, cheeks, sinus and to other areas of your head and neck. Dentist will treat a tooth abscess by treating the cause and getting rid of the infection. See your dentist ASAP.