My girlfriend put straight tea tree oil in her ear and now it burns can she use peroxide to make it stop or what should she do??

Hello, Anon. Thank you for writing today.

Pure essential oils can burn, and are meant to be diluted.  Applying a bit of olive oil or other vegetable oil to dilute it should help get rid of the burn.  If this does not help or if you are unsure, ask your pharmacist for advice or visit a local Doctor's Express (or another such facility).  I wouldn't recommend using peroxide. It may worsen the burning effect. 

Helena