Positional plagiocephaly(flat head)

Anybody's baby have/had positional plagiocephaly(flat head) due to favoring one side while sleeping. Our son has it and the doctor gave us some recommendations...towel on the left side so he turns to the right side. Any other recommendations? If your child had it, did the recommendations fix it or did your little one need to get fitted for a helmet? If so, how long do little kiddos have to wear it?

On another note...our boy just turned 4 months! His sticker had to be put on a stuffed animal because he was trying to pull it off😂