Under Tank Heat Pad or Heat Lamp- which is best

Maizi, not a problem at all. My temp probe is on the bottom on the glass, directly in the center of the mat. It's topped by a small reptile carpet and finally substrate. The hide is over everything.
As long as the temp is regulated, it won't get too hot inside. I figure that if the temp probe maintains 85-90F, in his hide should be a few degrees less. He's a happy guy.

Personally, I don't think a heat lamp is going to keep a good warm temp at the bottom of the tank, unless that is, you have it a few inches from it.

I rely on the heat mat to keep the inside of the hide warm, since he is mostly hidden anyway. The lamps are only to heat the air on that side of the tank as at night and in the winter, the house air temp can drop into the mid-high 60's.

Perhaps that's overkill, but the warm side will ensure that he's not going to get the opportunity to freeze or be uncomfortably cold. He's not dumb and will move there after feeding and on cold nights.

Hope this helps explain a little..

I started with using ceramic heat lamps, they can be effective. I used them in 20 gallon long tanks.
Whether using UTH, ceramic heat lamps, heat from the bottom, on the back, heat from above, or ambient heat, etc, the main thing is making sure the heat source is regulated with a thermostat.

I personally started with ceramic heat lamps, then later switched to ambient heat, with a piggyback thermostat setup.

During the winter, I use both. It gets chilly during the night and when I'm not home. Also, if your snake is one that likes to bask, it's nice to see them perched up on a branch or toasty half log.