I was on Xgeva for 2 1/2 months after my last chemo infusion. I developed necrosis of the jaw, as a side effect. A hole in the soft tissue in the bottom of my mouth opened up. I could feel bone with my tongue. Ultimately, the necrotic bone tissue came partially lose and dental surgeon pulled it through the hole. The hole closed up on its own. It was kinda cool in a weird kind of way. No problems now, and, no pain ever in the whole episode. Off the Xgeva. This is a rare side effect by the way. Good idea to watch for signs of it anyway.