I feel for you melamine is some horrible stuff. I do not keep snakes in anything but tubs but I do have a lot of negative experiences with that material. Putting something on the glass would probably not resist pressure from the animal well. The only thing I can think of would be to bolt a piece of better material to the inside of the enclosure on that side with enough overhang to cover the gap. If the material is strong enough and bolted well, you may actually be able to pull the warp out over time by periodically tightening the hardware. It is not going to look good but there is probably not much else u can do outside of replacing the warped piece. If you do try the bolt method make sure you use some really good sized washers otherwise the bolts will pull through that wonderful material.