Theres a piece of gums hanging out of one of my cavities what do i do?

Put down the computer. Pick up your phone. Call your Dentist immediately! Cavities are infections that gradually spread through circulatory system to other organ systems. There is no magic product, poultice, pill, app, video, OTC, mouthwash, or as-seen-on-TV that will cure dental infections. The longer you delay, the bigger the infection gets, the more treatment costs.

That tooth needs to be evaluated by a dentist to see if it is restorable. It may not be.

That piece of gum-like tissue is the result of living pulp tissue surviving when exposed and continuing to grow when supplied by the original blood vessels at the tip of the root. If the tooth can be saved it will be with root canal therapy. Please see a good dentist as soon as possible.