I was in a fight and the guy put his fingers inside my lower gums he had wounded my mandibular frenum and its wide but not deep . will it grow back ?

Injury: It will likely heal up without a problem. If the frenum was truly torn through and through, it may not heal back exactly like it was. This is really of no concerns as long as the soft tissue heals. Any swelling? The main thing to keep an eye on is to make sure you aren't getting an infection. As long as the is no large amount of swelling, pus, or you are not getting a fever then you should be fine