If it is just localized to this particular area on your body like you have shown in the picture, it is most likely that you are developing an allergy to the leather strap of your wrist watch. Also due to the irritation with allergy and sweat accumulation you seem to have scratched that area quite a bit. It is a minor issue and easily solvable. Stop wearing leather strapped watches and you can apply Momate F cream twice a day for 14 days and Tab allegra 120 mg twice a day for 10 days which will provide relief and then you can stop the medical treatment and in future avoid wearing leather strapped watches. Also, kindly take the treatment for the recommended time only and do not continue to use them beyond the above mentioned duration. However, if there is skin involvement beyond what you have shown in the attached picture of your wrist, you should see a dermatologist and get a detailed full examination before takin any treatment.