Mary Kay markets a very wonderful formula of concealer for your situation that does not flake. Another good option would be to use Maybelline brand concealer.
concealer
It is incredibly difficult to determine which concealer of the thousands on the market is the best for a face with freckles. Some good ones include The Body Shop's Ultra Smooth Liquid Concealer and Boi - ing by Benefit Cosmetics.
Avon
You can use a concealer to hide the contusion. Pat the skin with the contusion with the concealer and gently blend in the concealer with the surrounding skin to hide the bruise.
maybelline makes AMAZING concealers especially dream lumi touch highlight concealer. covergirl does ,too
For dark spots, you need a yellow based concealer. This will give the best overall coverage.
You can but ts best if you use a liquid concealer on first then the powder on top so it will stay longer.
First cover up under eye circles by using a concealer brush or your fingertips to dab concealer under your eyes. Apply the concealers under your eyes and blend the concealer in around the edges. Simply dab the concealer with the tips of your finger or brush in order to blend it. Next, apply the concealer to acne and spots. Dab your concealer onto the top of each mark, and then blend softly outwards to your skin. Use a thin layer of concealer to avoid having a caked-on look. If you have acne, avoid using your fingers to blend the concealer because using your finger can spread bacteria. Lastly, you have to set your concealer. Use a loose or compact powder foundation to set your concealer, so it does not easily wipe off.
Concealer is sort of priming the face. If you have circles under your eyes or a blemish you put the concealer on them, blend a little and then, apply foundation. I use MAC concealer and a q-tip to smooth it out.
Concealer or powder.
I have combination skin and I get blemishes in my T-zone and need to use concealer every day. The best full-coverage concealer is probably the MAC studio effects concealer, because its so thick but light and gives a really nice heavy coverage so it hides all redness and dark spots. For just a cheap, everyday concealer is the Maybelline NY dream mousse concealer, because its super light and airy and has quite excellent coverage. For under the eye concealer, the best is Bobbi Brown, but just for a cheap drugstore one, the Physicians Fomula stick concealer or The Body Shop tea tree concealer stick are both good.
Concealer is way too heavy to put over your whole face. I would say no, don't use it as primer.