Facecrooks.com has some tips for dealing with the possibility of a hacked Facebook account.
Attempt to Reclaim your Account -If your account has been hacked, your best bet is to visit the Facebook Help Center and attempt to reclaim your account. For more information about keeping your account secure, visit this Facebook Faq.
Change your Passwords – The hacker obviously gained access to your email address and password somehow, says Facecrooks, so you need to make sure you change the password to your email address immediately.If this password is you access to other secure sites as well, change them too.
Run antivirus: It is possible that the hacker gained entry to your computer through a virus or other malware. Facecrooks urges you to make sure you have a current and up-to-date antivirus program installed on your computer, and do a thorough scan of your system. If you accessed your Facebook account from another computer, then let the owner of that computer know of the attack. They will need to scan their machine as well.
Notify your Friends & Family – Getting hacked can be an embarrassing and humiliating experience, notes Facecrooks, but don’t let this discourage you from notifying your friends and family of the incident. The hacker may use your account to send them malicious links and to phish for their personal information as well. By alerting them immediately, you can help them avoid the same situation you have found yourself in.
Lastly, says Facecrooks in conclusion, take a deep breath and try not to panic! It may take a little bit of time and effort to correct the situation, but quick action on your part can help to minimize the damage caused by the incident and help get things back to normal.