I myself would be worried if my CPU reached 90+ degrees. Did you build the computer yourself? If yes you should feel comfortable enough changing the thermal paste or swapping your stock cooler for something better like the CM Evo212. If you are not comfortable removing parts inside your computer then you could watch some guides on how to do it.
The best thing would be to do both, change your Thermal Paste and swap to a better cooler.
Good luck : )