Indian sand boa feeding issue

[Pika002]

Hello everyone. My Indian sand boa, 1.5 year old, probably male(for the smaller size) hasn't being eating for 3 weeks. His appetite is dropping since beginning of September, his last meal was only a pinky. Temperature in his cage is 84f during day and 72f at night. I'm also using heat panel to create hot spot for him, since he likes to "bake" his stomach after meal. The temperature has dropped due to climate change, which I think might be the reason. But there is cold season in where Indian sand boa lives, so I thought it is okey for some temperature drop in autumn and winter.

My questions are:
Does Indian sand boa fasts during cold season?
If so, how long does it last? Must I assist feed him?
Or, I'm I simply keeping temperature too low?

This week I offered thawed mice to him and he seemed interested, licking it around, but eventually left away without eating it...
Any advice please? And sorry for my bad English.