Lindsay Lohan -- I Don't Owe That Betty Ford Worker a Dime!

It took her six months, but Lindsay Lohan has finally fired back a response to the Betty Ford worker who claims LiLo assaulted her -- and to no one's surprise ... Lindsay is pinning all the blame on her.

Lindsay allegedly got into it with Dawn Holland (now going by Dawn Bradley) back in December 2010, while Lindsay was in rehab. Bradley filed a lawsuit last July against Lohan for the alleged incident, claiming assault and battery.

Attorneys for Lindsay filed their response in Riverside County Superior Court on January 10, claiming the entire incident was provoked by Bradley ... so Lindsay shouldn't have to pay her a cent. Lohan claims anything she may have done was done in self-defense.

Lohan also wants the court to force Bradley to pay for her court costs, plus any other relief the court sees fit.