Angular chelitis is so painful! If you’re prone to it, try a vitamin B supplement. I think it might be caused by low b12 levels but if you get a combined vit B tablet that won’t hurt.I'm prone to getting really painful split skin at the corners of my mouth. I googled it and am pretty certain it's a condition called angular chellitis which can usually be managed in its own. However when I got it a few months ago, the sores got infected so I filled in an online form with my GP and she called me back. I explained what I thought it was. She said no its a cold sore. I said it most definitely wasn't, but she wouldn't have it. After grilling me for about 5 minutes she grudgingly agreed to try an antibiotic cream but she wasn't convinced it was infected. All of this was done over the phone and she hadn't asked me to supply photos. If she had seen me in person or asked for photos she would have seen the great big oozing crusty infected scabs for herself! I felt stupid for making a fuss it did clear up with the cream though so I was right