I had a popcorn stuck in my molar. the inflammation has gone down but still, it is somewhat swollen and sensitive. ithurts to brush/eat from there. will the gum grow back?

Yes: If you had healthy gum before the popcorn incident then your gums will recover.

Usually: A "popcorn abscess" is a localized infection caused by the hull of the popcorn lodging between the gum & tooth. If the hull is washed out and the area is debris-free, then you have a good chance that the gum swelling will subside & the area return to normal. You should see a dentist to see if there was calculus (harded tartar) at or under the gum. If so, that area will not heal without dental care.

Consult a dentist: Popcorn is a common problem, as husks from kernels can migrate under the gum causing irritation, swollen gums, pain, and bleeding. This occurs even when the patient believes that it has been removed with brushing or floss. These husks usually require professional removal with the special instruments that dentists use. It is best to consult a dentist to be certain.

See a dentist: Sounds like gum disease. Depending on the state of your periodontal health the gum may grow back or not. Don't wait you need to see a dentist as soon as possible.

Time: If the irritant is gone (popcorn skin or kernel) then it should go back to normal. Make take weeks to fully resolve. Keep it clean, but gently. Do not eat in such a way to put more pressure on it. If not better in 2-3 weeks, see the Dentist. Good Luck.