What's the background information? The only thing he can do with an I.P. is down your internet and locate you to a broad area (such as a specific city).
You could also release your ip in .exe box then obtain a new one if you are that worried.
Btw whoever has pmed you last, if they fill up a pm with spaces then take 5 off they can then type whatever, and make it look like they are someone else.