###Human: Why am I having hive like rash on my hand only? ###Assistant: Hi. I have gone through your case. In my opinion, you have got an allergic reaction to something like it could be an insect bite or it could be some reaction to wild plants or weeds. It is good that you have used Hydrocortisone and I will recommend you to use it for another week. Apply two times a day for next seven days. And now about brown or black pigmentation. Then remember that it is a natural response of our skin to heal or combat any trauma with hyper or hypopigmentation. In your case, there is hyper pigmenation. Leave it as such right now. Because any creams, if used right now, will start itching and redness. And your lesions are fresh so I do not recommend it right now. Either this will lighten itself with time or if required we will try atleast after 14 days. For more information consult a dermatologist online -->