Thanks for writing in.
You may have what is called as sebocystoma multiplex.
It can cause recurrent sebaceous cysts in axilla ,chest trunk.
To prevent infection you can use medicated soap like SOAPEX soap.
Also to prevent cyst from occuring you can undergo laser ablation
of area to eradicate sebaceous gland
in the area.
I encourage you to visit a qualified dermatologist
for proper advise and treatment.
Hope this helps.
STD & leprosy