He looks very thin and ill! He needs to see a vet and get faecal tests done, there's very little you can do at home for him now without potentially making things worse.
He could well be an enigma gecko - if you get better pictures of the eyes that will help. That positioning could be star-gazing (as enigmas do) but also a reaction to pain/being scared.
Do you know what the temperatures are? Particularly under the light.