I got hacked. How do I change my facebook password?

[Severos]

ok,
first things comes first: do not even bother thinking of what Rohit or Feis said, using such ways is probably the reason of people getting their accounts hacked.

the only reasons i can think of for the expired or invalid link is that the account logged during the process or that you took too long waiting at the page before clicking the link which caused the season time finish.

as for recovering your account, only way i can think of is using the i forgot my password button, there are various options there, so try them all and see which one works for you.

on a last note:
don't open your e-mail/FB account or any other account without using the httpS protocol instead of http, also try not to login at all from public networks.