Leopard Gecko appetite problem?

this is a problem that i hate getting my leo is not eating! I see him ocassionally drinking but thats it! its not impaction becuase i use reptile carpet. hes looking skinnier all the time and he hasnt been eating for a loong time, i dont wanna put crikets in becuase they'll nible him, ive tried putting mealworms and waxworms in a bowl and he hasnt even touched them. i even tried getting these appetite enhancing gecko bites that didnt help at all! He is a juivenille and i want him to grow before he dies, you all always have great answers for me can i get some help please!!! dont want him to die!! oh btw his temp is mayb a little low around 83-85 degrees but i did'ntt think that is the cause of this whole problem.