like the ones by Physicians formula
do they really cover up redness?

they dont "cover" up redness. they calm the swelling down so it is less noticable.

Well yeah they cover redness but you have to put on a lot of the green to completely cover the redness and then you have to put regular concealer over that so it eventually looks like a cakey mess. No redness but it looks bad. I suggest you just use spot treatments and regular concealer.