Welcome, and thanks for your question. My name is XXXXX XXXXX I will do whatever I can to try to help you.
Lesions can appear on other parts of the body even after the antibiotic has been completed. It may be that the lesion on your scalp is from a different type of bacteria other than staph, or it may mean that the staph is resistant to clindamycin. I would advise your seeing your medical provider for culture of fluid from the new lesion to determine what bacteria is causing the infection so you can start on the correct antibiotic again. I'm sure that's not what you wanted to hear, but it is the safest course of action.
Please let me know if you have questions.