When I try to draw something with flash, it should allow me to use pressure sensitivity, but the icon isnt showing so I cant use it.
Im using a bamboo tablet btw.
Anything I can do?

reinstall the tablet drivers

I would do tihs in order.

Unplug then replug your tablet, if your computer is like mine it looks for the drivers when its plugged in.
Reset computer, sometimes it resets the drivers and fixes itself.
Find the tablet drivers and reinstall them, if you don't have the disk, Google the drivers.

And if it doesn't work after THAT. Call up the company and get some help from them.