It looks that way because I used a dremil to cut it and it was actually melting it more than cutting. There is a small gap between the plexiglass and the heat bulb. It's small but it's there. Also I've had this set up for a few months now so I think it's ok. If I notice a change tho I have some metallic tape I could use. Thanks for the ideaIf you notice the plexiglass starting to warp from the heat, cuz it probably will, you can line the rim of the hole with tin foil and it should protect it from melting or warping. It works on regular plastic