Get a lawyer....NOW!
Stop talking to the complainant...NOW!
Stop talking to anyone about this besides your lawyer....NOW!
You can remain silent but it's not just going to go away. A very serious allegation has been made and without some statement from you (only with a lawyer's presence and approval), they only have her version to work off of. Her version makes it appear you are a bad,bad person. Unless she is very delicate or you were...vigorous, there should not have been any bruising from foreplay...again looks bad to the police.

