I think Alice hit it right on the head. Taking less mestinon, I don't think would relieve the pain, but sounds like you strained the muscles and as the days went by the pain lessened.
I know when I take to much mestinon, my vision gets even worse and my tongue twitches and swells. But when I do to much than my muscles hurt more than usual.
Please let us know what your Dr says tomorrow.
Good luck and feel better