Ron,
You don't have to undergo any type of treatment to get angular chelitis. It may or may not be related to your situation and/or treatment.
The fungus that causes this is present in almost all people and all it takes is ideal conditions for it to take hold and cause a problem. It is part of our normal oral flora and saliva etc. usually keeps it at bay.
The vit. E may help but, I wouldn't put all my money on it. You mentioned cracking so the causative agent is now deep in the skin in a moist nutrient rich environment. Call your doc as soon as you can and get a prescription to slay this nasty beast.
Cheers,
Mike