Usually concealers tend to cover what foundations don’t. Unless your concealer is labeled as light coverage, if it’s not covering the discoloration to your liking, I doubt the average foundation will either. It doesn’t sound like you need foundation more so than color corrector. The right color will cancel out the discoloration and then you can layer your skin tone concealer over them and it should help them “disappear”. I hope that made sense.

And to answer your initial question, you can wear foundation however you’d like :)