Temperature for corn snake

Hi everyone! So I just got a baby corn snake at the end of October. The breeder said it didn’t need heat. However, I knew from research that it would need a heat source. So I put a heat mat on the side of the tank. That only raised the temperature by 5 degrees. I attached another mat on the underside of the tank with a thermostat. That only raised the temperature by 2 degrees so now the hot end is 72 degrees. He ate before I attached any heat sources but wouldn't last night. What should I try next to raise the temperature? Shouldn't a higher heat encourage digestion?