Hi there,
I think it is best to leave the area uncovered if at all possible, but there are times when it's just not going to happen. I've treated my chest three times and I wear v-necks at home. While I work, I wear tops that cover the area--turtlenecks in the fall.
It is important not to actually bandage the area you are treating. You may find, while treating, that the fabric from your shirt rubs and irritates the skin. The cream itself will make your skin itch and burn, and the fabric may add to that feeling.
If you have questions about covering your treated area, consult your doctor. He/she should be able to advise you on how much cover is too much.
Best of luck with your treatment!
April, SkinCancer.net, Moderator