What is this called?

[domcel]

Seems like a strong ass masseter but his mouth is open. May be a grey moment from me here but I want to get some kind of filler or something around that area to reach that, because im recessed around masseter area but I dont even know what to search for fillers here does anyone know what particular thing this is and/or what kind of procedure could be done for it. Thanks!

 

[true.heisenberg]

it is masseter, the reason you can see it even though his mouth is open is just because he's lean