hammer gowth

I have a SUPER tiny hammer coral. Its starting to have some tissue recession between the heads. it only has two heads and up until about a week ago the tissue between the heads went all the way down and connected. Now the tissue is receding back to where it only has tissue on each individual...

I’ve had this hammer since October. He’s grown a new head and his original head is growing in size. What kind of hammer is he? And is that growth rate slow or normal? Several pics under several spectrums and a video attached.

Hi All, Lately (past 2 months) I'm noticing that my hammer is not growing over the skeleton but outside. It opens up normally so I don't think it is dying! Is this behaviour normal? Should I keep it this way? Should I do something to make it grow bigger?