You can not unblock yourself from someone else's account unless you have access to that account on your own.
Someone Block Me On Facebook How Can I Unblock Myself
However, there are a few things that may make you really feel much better:
: > You can still see whatever they publish openly (as long as you aren't seeing it as/from the obstructed account). You simply won't see what they publish to good friends.
: > You can still watch their public account by visiting it's one-of-a-kind LINK (www.facebook.com/firstname.lastname, generally).
: > You can make a brand-new profile and hopefully include the person that obstructed you to this new account (claiming to be somebody else). Nonetheless, I see this as a last option and also do not suggest it due to the fact that it can backfire and make things even worse than initially. This protests Facebook's TOS, likewise.
: > If you understand their Facebook email address, you can create them an email from a normal email account as well as it might most likely to their Facebook inbox (I assume this still works).
: > There are other ways to contact the person (text, email, smoke signals/pigeons, etc.).
Besides those things, you can inquire to unblock you. If they don't, really feel much better recognizing the individual that obstructed you doesn't care anymore (if they relatively never cared, really feel even better).
Don't seem like you can't get a message to he or she, since you can if you truly want to.