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.