NEED HELP - Baby Jungle Carpet Python Heating

Hello, So I recently purchased a baby jungle carpet python, and was recommended to use a small cage. The cage I am using is 12 in L, 12 in W, 18 in H. The problem I'm having is I cant really regulate the heat, I am limited by the width of the cage. One heat lamp takes up most of the screen top. The "hot side" is around 88 F while the "cool side" is around 85. It is hard to keep the "cool" side "cool" while maintaining heat. If you have any ideas or suggestions on how to regulate the heat better on a small enclosure I would be very grateful. The snake is 3 months old.

When you say hot and cold "side", are you literally referring to one side and the other or the top and the bottom? As long as the top is staying warmer and it's cooler toward the bottom of the cage you shouldn't have an issue, there just should to be a cooler area for them to go if they want. Whether it's front and back or top and bottom makes no difference. I would also keep an eye on your humidity if you're not using a tub setup, some cages can dry out pretty quickly if you don't keep an eye on them.

I started my baby carpet in a 29 gallon tank with a screen top and a 100w ceramic heat emitter positioned just above the screen on one end.

Those temps are pretty high. With an enclosure that small, you are better off with a heat pad under a small area. Shoot for about 80 as an ambient temperature with the spot where the heat pad slightly warmer.