I get bruises on me every where all the time and half the time I can't tell you why!
Try using a cotton ball and dabbing foundation, that way it won't be too heavy and then dabbing transparent powder over the top. If you can get a corrector concealer then that may be even better, especially a pink or peach based one as they're designed to neutralise under eye circles and redness and stuff like that. Fake tan can also help cover them. Sally Hansen do a leg spray which is like a fake tan and cover up in one - it's called airbrush legs, it's a wash off one so it's not like normal fake tan where if it goes wrong you're stuck with it so it can be quite useful.
Arnica is really good for helping bruising heel, I was recommended it by someone a while ago it's not expensive and it did seem to work, you can get it spray, gel and I think tablet form.