After recovery from a modified neck dissection for oropharyngeal cancer, the client receives external radiation to the operative site. for which most critical reaction to the radiation should the nurse assess the client?

External radiation is sometimes necessary even after a modified neck dissection in order to be rid of cancer cells that can grow back into tumor. The most critical reaction to external radiation nurse should look out for is open sores in the mouth and throat which need to be treated, as well as mucosal edema.