Red dots on the inner side of the arm may be folliculitis, prickly heat, cherry angiomas, etc. The treatments for different causes are different, so you should consult a doctor in time for judgment and targeted treatment. 1. Folliculitis: the common manifestation is the formation of red papules around the hair follicles, which may be accompanied by red, swollen, hot and painful inflammatory reaction. First of all, attention should be paid to skin cleaning, avoid injury. If the condition is mild, mupirocin ointment, fusidic acid cream and other antibacterial drugs can be used externally; if the condition is more serious, it is necessary to follow the doctor’s instructions with oral medication, such as doxycycline, cefuroxime and so on. 2. Prickly heat: red spots on the inside of the arms may be due to the blockage of sweat pores in a hot and humid environment, and the skin appears to have raised red papules and small blisters. Generally, prickly heat can disappear on its own after cooling and drying treatment of the skin. Severe symptoms can be treated by local topical application of medicines such as glycerite lotion, prickly heat powder, hydrocortisone solution, etc. If necessary, antihistamine medicines such as loratadine can also be taken orally. 3. Cherry angioma: mainly benign proliferative changes of blood vessels in the skin, which can be removed without treatment in general, through laser, freezing and other treatments. In addition, red spots on the inner side of the arm may also be caused by skin allergies, urticaria, etc., which should be judged by a professional dermatologist in time and guided by treatment.