Hi... Its unfortunate that you are dealing with this problems.painfull pimples indicate infected acne.Acne n dandruff are common skin problems. Dandruff is a type of fungal infection. It increases with more sebum production. Dandruff can cause both hair fall n acne.use topical antifungal preparations n if required oral antifungals. Probable causes of acne n hair fall include PCOD, thyroid abnormalities, androgen excess, odesity, insulin resistance, other endocrinal abnormalities, stress, pollution,nutritional deficiencies, genetic issues, hereditary problems, acute or chronic illness, ect. Identifying underlying cause n treating appropriately is of atmost importance. Treatment options include oral n topical antibiotics, retinoids; regular use of sunscreens, lasers, chemical peeling,ect for pimples. PRP ,mesotherapies, lasers, after controlling dandruff for hair fall.I would suggest to consult a dermatologist n get appropriate treatment. Hope this ll help you. Have a good day