First off, bringing your peep closer to the knock will make you shoot lower. If it doesn't you probably have major form problems. Imagine being at full draw and somebody moved the peep down. You would have to raise your release hand to see through the peep which would point the tip of the arrow more downward.

5 1/2'' on your peep will get you close, but closing your eyes and drawing to a point that feels comfortable as descibed in prior posts is good advice.

What really concerns me is your anchor. If you are using a caliper release, a common way to anchor would be to place the string on the tip of your nose, your trigger fingerunder your ear lobe, and your thumb tucked under your jaw bone. The only anchor related to the corner of your mouth would be a kisser button. You didn't mention if you have one of these or not. No part of the string or your hand should be touching your chin. If it is your draw length may be way to short.

I hope this helpful. If not I just wasted an hour typing