Advice on soreness/rest days?

Hey guys!

I've found myself in a predicament a number of times, and I'm still not sure how to solve it. You see, I did an intense HIIT workout on Monday (total body, but I only felt it in my lower body) and yesterday I did an upper body workout. The only thing that is sore at the moment is my lower body, but it's only a little sore when I squeeze the muscles. I had a lower body workout (strength and pilates) planned for today but I don't know whether or not I should do it? Do you only work out if you have NO soreness whatsoever, or does a little not matter? Is two days sufficient time to wait before doing a workout that targets the area that is a little sore? Should I do another upper body workout if my upper body isn't sore?

Advice please!!!