H202 bath with weird result?

My wife and I took our first H202 bath this morning, I have been taking it orally for a couple of weeks with no problems but this was the first bath. Anyway, we only stayed in for about 25 min. each and when she started to get out the bottom part of both feet were a dark purply color, about the shoeline all the way around! After draining the tub and refilling with plain water to rinse off they quickly returned to normal color. Anyone experienced anything like this or have any idea what caused it?
Thanks
Terry Tweet