Roommate’s Gf Pissed On My Toothbrush (not A Joke)

Location: north Texas. Title pretty much explains it. First time posting on here but I’m pretty much at a loss for what to do now. Some context- my Roomate (21M) and I (20M) have not exactly seen eye to eye lately, but any altercation between us has been verbal only and minor disagreements at best. I’ve never done anything to harm him or his property or his gf (19F). As a matter of fact, I think I’ve only talked to her in person like 3 times, all of which were extremely brief and just me saying hi really. She dislikes me so strongly because in the past I had told my Roomate (who was my friend at one point) that he should break up with her because she cheated on him. As you can probably assume, he didn’t, and ever since then I’ve been living in fear that his girlfriend (who has a history of doing insane shit like this) was going to get me sick or mess with my stuff as I am gone for work/ school for most of the day. I found out last night, through a friend that was texting her, she did confess through text and i have the screenshot (if that will even do me any good). My Roomate IS planning on moving out soon, but since finding out what she did it’s genuinely hard for me to live there and trust that my property isn’t being tampered with while I’m not there. Other details- my Roomate did know about this, for what it’s worth. And his girlfriend doesn’t live with him. I know that it’s probably unlikely I can do anything about this but literally anything would help.