Remember, keeping the dome clean will keep it clear. Get a mild anti-bacterial soap, Cuticura is my choice, wash your dome 2 even three times a day--and it feels good too. Get some 10% Benzoyl Peroxide lotion--the cream is too hard to rub in, and some hydrocortizone lotion, mix about a pea size portion of each in your palm and rub it into your freshly shaved dome--right after a wipe down with an astringent like hydrogen peroxide or witch hazel. Don't forget to exfoliate too--although there's no hair the folllicles are still making oil and can clog up!
Finally, make sure you're changing the pillowcases regularly, at least once a week, and if you do wear a hat, make sure it's clean.
That's about it. Should clear up in a week.
If it doesn't check with the doctor, it could be a skin condition that needs some heavier hitting.