Yes rose water is a natural skin toner. But nature isn't safe always so do a patch test before using
Many factors contribute to the development of acne, including sebum and keratin production, acne-causing bacteria, hormones, blocked pores and inflammation. Excessive consumption of Oily/fried foods, processed foods, refined sugar and diaryHowever, more research is needed.
Dandruff itself does not cause hair loss. However, severe dandruff can cause a person to scratch their scalp so hard that they injure it.
Shampoo which contain active ingredients like pyrithione ,zinc, selenium sulfide, ketoconazole, salicylic acid, and coal tar can work to reduce dandruff. since there are many underlying reasons(as simple as stress) it is better to take an expert opinion first before using OTC shampoos
Always use a mild shampoo but do consult a dermatologist for dandruff