Folliculitis is an infection of the base of the hair shafts caused when bacteria invade the pores and multiply, causing painful, swollen 'pimples'. In addition to good hygiene and regular use of a shampoo, treating these spots may require a topical antibiotic cream or an oral antibiotic, such as the doxycycline that you are taking.
Unfortunately, sometimes folliculitis of the scalp can be difficult to treat. Often the oral antibiotics need to be taken for a prolonged period of time of weeks to months. Furthermore, sometimes a bacteria that is resistant to antibiotics is involved and changing the antibiotic regimen or taking more than one antibiotic at the same time may be needed.
Therefore, if you are not having any luck with your current regimen, it is time to see your primary care doctor
for reevaluation. You may even need a referral to a dermatologist
for further treatment.
In addition to folliculitis, you should rule out that what is going on is not something other than folliculitis. For example, seborrheic dermatitis, an inflammatory condition of the scalp characterized by itching, and greasy, scaly areas can sometimes be mistaken for folliculitis. Your doctor will be able to help you make this determination.