The lumps on chest are acne vulgaris
...also called pimples. Cause may be the teenage or genetic diathesis may be there. Stress,anxiety,sleeplessness
,sun exposure.oily and spicy food,milk steroid,iodine or isoniazide drugs...etc may exacerbate the tone lesions. Azithromycine or minocycline
may be taken for long time.istretinoin10 mg ma be taken till you get dry lips. Zinc sulfate
220 mg may be taken at night for long time. Apply clindamycine or adapelene gel at night on lesions.antiseptic body wash and face wash may be used.
Do not squeez or prick the lesions.
I hope you got my answer.
Dr. Ilyas Patel MD