BLUE TONGUE SKINKS

I just got a new Baby Halmahera but it wont eat it's food, The temperature seems good i keep him/her at a 40 gallon tank, it has a basking stone, Hiding cave at the cool end, Water dish, Feeding dish, and some plants. Im trying to feed it Wet Dog Food since the seller i bought it from said he usually feed it dog/cat food and vegetables. It has been 2 days now and it still doesn't want to eat im scared and confused any reasons why it wont eat?

First of all, what are your temps? Humidity? Halmaheras are 99 percent imported and often come in with parasites, both internal and external. For any imported animal I would recommend a check by an exotic vet immediately. I'd also move to a smaller cage, or section off to start. A 40g for a baby can seem overwhelming. Their nature is to not be seen.
Temps should be 95+ at basking
Humidity should be 80+

Yes, please provide us some more information so we can help you better.

Temperature ranges 90 - 100 so im pretty sure the temperature is not the problem, I just went to a vet and its actually alright there is no sign of parasites, i bought it imported but was captive breed. It just ate today but it ate such a small portion i think it only ate a size of its head and didn't finish the food. And another thing is it doesn't want to come out of it's hiding cave the whole day it just stays inside the cave. I put a basking stone, some stones, and plants on the enclosure but it doesn't rlly want to interact with any of them.

Side note: Cool side of enclosure 80, basking side of enclosure 90 - 100

So I would make sure temps are at least 100-110 in the basking side. What is your humidity? It needs to be at least 80%. Hiding is completely natural for your baby skink. It can take them weeks to adjust and be comfortable. Just offer food daily for now and make sure there is fresh water daily. Talk your skink and just take time getting it used to your routine and voice.