A good idea is to make a humid hide using sphagnum moss, that way your snake has humidity when it needs it. 45% humidity isnt the end of the world, its not the best but it wont kill him either. Also give your subtrate a good soak, not a puddle though, once you get that base moisture, its easier to maintain. And watch for dents in the eye, it can happen when their dehydrated.

Another way to raise the humidity is to use a larger water bowl, and place it under the heat lamp. And to go even further, get a bubbler for a fish tank and put it in the bowl.

And if you post pics of your setup we can help even more