Erm... can't you trademark Hot Mess?
Edit: Yup, you can. There are currently two trademarks for "hot mess", one is in shoes and the other is in tanning products. My recommendation is that you register your name, Hot Mess, in the category of music production and performance, then send her a C&D.
As long as you have a registered trademark put into place before she does, and your products are similar enough to cause confusion (which it obviously could in this case, I can open a fast food restaurant called Nike but if I get into the shoe biz I'm in trouble,) you're legally in the right. Actually, once you have a trademark you're obligated by law to reinforce your right as the trademark owner.
Here's hoping you decide to take the next step and register.
this is would be good.
