If it is rosacea, then it is not likely due to head shaving. Maybe it is just be more visible with the shaved head.
My wife had rosacea for years. Her doctor sad there was no cure, but some treatments may reduce the affects. In here case, in addition to the redness, she would get pimples and acne. After about 10 years dealing with it, she was treated for unrelated cancer in her stomach and the initial treatment was a high dose of an antibiotic. The rosacea disappeared and has never come back.