My next step would be to treat the lower levels of the cervical spine (neck) as the irritation is probably coming from there. It is of course most likely biomechanical in origin so perhaps ask your PT if they might tape you prior to a dance rehearsal to see if that assists you. Some active taping like K-taping concepts should be really useful as you will need to learn to move slightly differently to address the likely causes of this issue.

Best of luck