what is (temperature) too hot heat mat for ball python?

[Stewart_Reptiles]

my thermostat fluked over night and he was on 98 after eating overnight.
Any problem might happen you think? Thanks
PS
I dont want to touch himrp yet because he ate

Those are notoriously known to fluctuate and fail, and when they fail they fail wide open, I would highly recommend you to switch to a RELIABLE thermostat and make sure it is correctly set up (probe directly on the heat source outside the enclosure)