Please help me get his weight up

I have a rescue enigma leopard gecko I got him from a pet store that wasn’t feeding him. I’m struggling to get his weight up and I’m scared he might not make it. I’m taking any help and suggestions I can get because I don’t want to give up on him.

I have a rescue enigma leopard gecko I got him from a pet store that wasn’t feeding him. I’m struggling to get his weight up and I’m scared he might not make it. I’m taking any help and suggestions I can get because I don’t want to give up on him.