For the time being if your snake is young and small it probably can't reach the bulb but its still needs to be fixed. You need to get a screen to keep the snake from being able to touch it.
You may also want to check into radiant heat panels(rhp). Many using wood enclosures have good luck with them and they are much safer than your current setup.
Check out Pro Products. You can call them and they will ask some questions and get you exactly what you need.