Had abscess now gums have sack where abscess used to be?

Abscess: With the limited information you gave and not being able to personally see you, it's hard to know for sure the exact nature of your situation. However, until the cause of the infection is eliminated and the infection is completely resolved, you need to have a dentist follow up with evaluations and necessary treatment. See a dentist as advised.

Infection: You are probably having a tooth infection and manifested itself in a fistula .Taking Amoxicillin as you are doing now will make the infection goes away . But that would not cure the problem . I think it would be a great idea if you have your mouth checked by your dentist to treat the infected tooth.

Gum pockets: After a periodontal infection occurs the bone that was lost rarely regenerates completely. The pocket that remains will need additional treatment if you cannot get to the bottom of the pocket to keep it clean. Sometimes the solution is to trim the gums so that the pocket is eliminated or reduced. See your dentist or periodontist

Dental abscess : Dental abscess infection may spread to the face, sinus, brain or neck. Direct spread from a dental source can account for up to 10% of brain abscesses. See your dentist for a preventive treatment. Take care.

Abscess = infection: Source of infection must be resolved to affect a cure. Infection has probably damaged bone & gum. Antibiotics will control spread of infection only as long as you are taking the Med. Must see Dentist to determine cause of infection, cure, and follow-up reconstruction. Specialist referral may be prudent.