This sounds like a genetic condtion called keratosis pilaris, in which little plugs of keratin protein collect in hair openings. The usual place is the outer upper arms. It fluctuates in intensity, for no speical reason. If he has them there too, then it's in his family. No significance, and no useful treatment. Hopefully, he has some good points too . . .
Best.
Dr. Rockoff
PS: Have hom shoe his doctor at the next checkup, just to be sure.
Sometimes I get Ingrown hairs or what look like big pimples on my legs. A doctor told me to use a soap called pHisoHex. You can only get it at a pharmacy store. You do not have to have a perscription for it, but that is the only place to buy it. Please read to directions befroe you use it. DO NOT use on your chirdren and DO NOT use on your face. I hope your husband gets rid of them.
Joey22
P.S. Ask your doctor before you use it.