BLUE TONGUE SKINKS

Hi my Indonesian blue tongue big smoke is 9 months old, he's usually full of energy and constantly climbing but starting about a week ago he's been hiding and sleeping almost constantly, he normally loves Basking but isn't a tall, he's still eatting and drink just very tired, the warm side temp is around 30 celcius and the cool side around 27, humidity is about 80 to 90 %, should I be worried?

Update, he's now sleeping and hiding most of the day, I'm worried he's not drinking enough water also

What type of skink is this? They do like to hide and burrow. Mine will go days without coming out. You said it is still eating and drinking right? Depending on the species your basking spot may be low.