Iching rashes. It gets cured (itself). -

I just would like to say that 1 day before . I was outside home wearing shirt at 1 pm , then I suddenly started feeling a little bit iching at outer part of my biceps and before that everything was totally fine alhamdulillah. Then when my arm started iching I kept started scratching my arm and the whole day went and it was 11 pm when I took my shirt off , and then I saw a huge red bumpy skin (rashes) covering my whole upper arm (i.e. from shoulder to elbow outside) in this time only .10 hour from fine to uncomfortable seeing position. And then it started growing more till morning and on the other hand also (but a little). then in the morning itself I took bath and applied coconut oil and now it's been 12 hours since I am applying coconut oil every 3 hours I guess and it looks better a little bit only ,then do I need to worry about it or should I kept doing it till it gets cured (itself).-