Bio professor filing a lawsuit..?

So a couple weeks ago, me and a few friends were doing henna to fundraise for a service trip to New Orleans. The professor came by, she was really excited, and was telling us how her students had them, and she wanted it done too, so we did it on her. She was telling me how she wanted me to go crazy on her hand because she went to an Indian wedding and they had it all over their hands..

Anyway, so last week, she had to go to the hospital because she has sensitive skin, and it was reacting to the ink. I don't know how bad it was because I have not seen it yet, but I herd her hand was swelling. NOW, she is claiming that we "TRICKED" her into getting the henna done, which is a pathetic attempt at lying. She also said that we never asked if she has sensitive skin, which she should have known and have been aware of herself, I mean she's in her 50's, she should know her skin.

So today our group leader was telling me how the professor is planning to get a group of people together and file a lawsuit (a couple other people also had reactions to the ink, but it was just redness).

I think that this is ridiculous, especially because we had everyone signed a waver. Also, people should have known their skin type, and should ask if henna ink is okay on their skin. It's not our responsibility to make sure you take care of your skin, so many group organizations has done henna in the past and nothing has ever happened.

Do you guys think the professor has the right to file a lawsuit? I mean she has the right, people can sue over ridiculous reasons these days, but is it worth filing a lawsuit, or is she going over the top?
Opinions?