spots start as small lumps, become white heads, scab, scar

Hi,
Welcome to ehealthforum,
It is difficult to comment on the cause for the skin lesions that you describe without examining them and going ahead with further investigations (as suggested by examination findings) to confirm the underlying cause. Consider visiting skin specialist/dermatologist for thorough examination and evaluation to look for the underlying cause. Treatment as indicated (based on examination findings and investigations results) would be started to help you control the symptoms. Be in regular monitoring and follow-up with your treating doctor/dermatologist and report any new/abnormal symptoms immediately. Drink plenty of water. Take adequate rest. Maintain healthy diet and lifestyle.
Take care.