lawbuff:Coming from a woman, that seems like an odd statement.
That's a rather generalized perception of how women react to being slapped on the butt. I went through a similar action; I assured the fool who did it that if he ever tried it again that his prefix title would become "Ms." His attempt to gorilla-thump his chest turned him into a squirrel monkey.
This apparently was a first time incident with the OP. So what are you suggesting? That she cough up a $5000 retainer fee to attempt to file a civil suit over assault charges? Do you really consider that to be an investment worth a 15 year career -- especially at THIS stage of national crises?
OP -- I understand the element of concern, perhaps fear. Not everyone reacts the same to such incidents -- your fear could be because of something that transpired in your past; or it could be something about the guy that you simply don't trust.
It's unclear how long ago this took place, but it doesn't come across as "current" if you state it has affected your work performance because of your fear. An option is to discuss the fear with your Doc to determine if you should remain in that environment, or seek employment elsewhere.
The fact is that the employer resolved the situation. What occurred is in the coworker's records. Any suggestive statement, bad behavior directed to you and coming from him should be immediately reported. If it continues, contact EEOC. But, at this stage of events, I don't see grounds for a lawsuit.
Maybe an attorney would. Talk with an attorney.