Rika Ishikawa has been diagnosed with jaw inflammation and cyst.
She was feeling ill and was examined by a doctor, which reported that there was pain on the upper right side of her jaw. She missed the 5/21 Dream Morning Musume concert because of this.
Jaw inflammation seems to be pain in the jaw and after doing a little research jaw inflammation could actually be a symptom to an even bigger problem. I hope Rika isn’t in too much pain by this and hopefully for Rika this will be a short term problem that will heal soon.