bv2929 said:
Since I'm going to switch to the foam, should I go a couple days without any Rogaine before starting the foam in order to maybe clear the residue or (hopefully) allow the dermatitis to clear up? If so, how many days should I go without? I don't want to lose any ground. Any advice?
The general principle is that you should not apply rogaine foam to any red or sore areas. Ideally, you should get experienced/medical advice. Personally, I go cautiously with a weak hydro-cortisone cream - and only occasionally and irregularly - to clear up problems or redness and soreness. This way the soreness/redness/itchiness usually clears up in a day or so.
All this assumes, of course, that your difficulties are comparable. They may not be.
Other things being equal, I would leave it for a few days and see what happens - does it clear up, etc? A more cautious approach might advise leaving it rogaine-free for a week, or so.
I hope this helps.