What Do Small, Round Bumps Under The Scalp Suggest?

Hello, My wife has developed small round bumps under her scalp.They feel like small peas 1/4 inch or so in diameter .There are only two or three toward the back of her scull .They do not itch or erupt ,If she could not reach them she would not know they exist .They seem to flare up somewhat when she is under stress or when she is anxious.Our dermatologist prescribed a topical antibiotic ,but that offered little relief . We would appreciate any ideas .Thank You