Gum receding around bottom incisor tooth, what to do?

Peridontist. See a periodontist for an evaluation. Cause should be determined, further recession prevented and treatment for severe cases.
Disease or position. Two major causes of gum recession around lower anterior teeth are gum disease or teeth positioned off of their bone support and therefore undergoing untoward stress (or a combination of the two). You may need to see periodontist, orthodontist, or both. See your dentist for evaluation and possible referrals.
Gum recession !! Gum recession is not a normal phenomenon! gum recession is a sign that something is amiss. Either clenching or grinding as a parafunctional habit, improper homecare, etc are the main reasons these things develop. There can be other secondary reasons like high muscle attachments, but rule out the obvious is a good first line of attack.