Sore pimples on scalp

I have painful sores on my scalp.  They are swollen and painful to the touch.  When I squeeze them they bleed, but the blood is watery.  

Sometimes the sores go away entirely, but other times I seem to get many of them - maybe 5 - at the same time.

I see from a Google discussion on the subject that this is quite common, but no one seems to know the cause.

[Bhupinder Kaur, MD]

Hello,
The first possibility is of a boil or ingrown hair. Apply warm compresses on the boil and keep the area clean. Drainage of the boil is done only when it becomes soft and forms a head. Take some over the counter pain reliever, apply a topical antibiotic cream and consult a doctor for examination and antibiotics prescription.

I hope it helps. Take care and regards.