Another drywall question
As stated above, if there is still at least one layer of paper over the core of the board it can be "glaze" coated with mud and painted. You will need to prime before mudding with oil based primer, lightly sand the entire surface (the primer will tend to make the loose paper "fuzz" up), coat the entire surface with 2 or 3 coats of joint compound, sand, prime again, and paint. Another layer may be your best bet. Or hire a professional.........
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