Yesterday I was playing cricket match during night. While fielding I dived on the grass twice. I didn't get any bruise or cut on my hand, but I brazed the ground hard. I came back home and washed the area with water. There was nothing I could spot. Just little redness. Today by evening, the area started itching and by night it had spread to almost 80% of my hand. I can also see some small bumps and very small blisters, with redness all over the effected area. I took bath in neem water and applied one antibiotic ointment. What is the cause and what should I do to cure it ? Could this be contagious as well ?