I have a european stock HTC One SV (no root), which received the OTA update to Android 4.2.2 and Sense 5 when it was released (that was last November or so). Since then, the option to use the front camera disappeared from the Camera app. I can't recall clearly but I'd say that the camera app showed a button with some kind of "rotation" icon, and also I was able to use it with Skype. Now there is no such option.
I've cleaned up the app data... is there anything else I could do? Is it a common problem after the update? (although I didn't find anything by searching the forum...)