Aka Orf. Yes be careful not to touch it with bare hands as you can catch it and it is painful.
There are plenty of threads on here about Orf. My treatment would be to spray with Net-Tex Bactocyde (a disinfectant), and put out lumps of salt (rock salt ideally), which help to dry the sores up. And separate the affected ones to stop it spreading. You don't need antibiotics unless it gets very bad and infected. It will clear up by itself.
If your sheep are breeding ewes and they are still milking then check the udders for sores too and treat.
I had it one year, and since then I have had rock salt available all the time and I've never had it again.