Heat mat not warming up the enclosure?

So I got my first snake on Thursday. I got the enclosure with her, plus a heat mat, a thermostat and a normal light (not a heat lamp). I set up the thermostat and everything, but it seems like the heat won't go up in the enclosure, it's constantly between 21-24 celsius. Highest it's been is near the cave on the warm side, it reached 26 at one point. I know that's not enough on the warm side, and I don't know what to dooo... I have a temp gun and I've pointed it on the soil, and some of the branches that are higher up, but it doesn't change much. The cooler side is about the same temp as the warm side. Should I just ditch the heat mat, and get a heat lamp and something to keep the enclosure warm at night? The bottom of the enclosure is warm so the mat is warming up something, but the air doesn't seem to warm up, or am I just measuring it wrong? Ahhhh I feel so incompetent, any help is appreciated!!! 🙏🏻