Hi I Have A Ringworm Mark On My Arm Would

Hi I have a ringworm mark on my arm would it help if I put savlon on it which is an antiseptic cream or not and it seems to be getting larger than when I first noticed. It's very dry and itchy but I try and moisturise it but never helps. I do a lot of horse riding so I was wondering if that has caused it and I have no pets but the horses are all up to date with jabs