There are many factors that may be related to contact dermatitis, common warts, herpes sweat and other diseases. 1. contact dermatitis: hands in contact with allergens or irritants, there may be allergic or irritant reactions, there may be a lot of raised dots, it is recommended to avoid suspected allergens or irritants, under the guidance of the doctor to use antihistamines, glucocorticoid drugs, etc. treatment. 2. common warts: a kind of HPV (human papillomavirus) infection caused by superfluous organisms, in the fingers, the back of the hand and other parts of the raised pimples the size of a grain of rice, a single or multiple appearances, usually asymptomatic, and part of the self-consuming. 3. Sweat herpes: sweat herpes etiology is unknown, may be related to local stimulation, ringworm infection, mental factors, mainly in the hands of multiple small blisters, pinpoint to rice size, local itching, pain, flaking and so on. Hands grow a lot of small dots bumps should be timely to the hospital, under the guidance of the doctor symptomatic treatment, so as not to delay the condition.