Spacepain

I've been on Benzaclin (sp) but since the stuff is supposed to be applied twice daily and I cannot bear it during the day. I apply it only at night before bed. So my doctors having me start benzaclin than a 1/2 hour or so later when the stuffs dry, apply Retina A over it before bed. Any forewarnings on Retin A or any mixing the two ahead of time? I was told I'll get an initial break out with Retina A, but anything else beyond that?