One of my Zwartbles gets this in the summer months. The first year she got it (last year) it was dreadful and extensive. Most of her abdomen looked like your sheeps face does. Her ears were also very bad. Caused/aggravated by sun,midges and flies apparently, so is much worse in the daytime of the warmer months. I tried lots of different things on it last year, but it had already got bad before anything started to help, so this year, I started to 'treat' her ears in March and her abdomen area immediately after shearing. I apply Sudocrem to her ears and Udder Cream to her belly every day. If I ever miss a day, it is worse, so it does require commitment. She also has access to a field shelter to get out of the sun. Her abdomen has remained almost perfect this year and her ears much better than last year. She will now stand in the middle of the field unrestrained for me to do all this and gets a bit of digestive biscuit afterwards. I am vigilant about fly protection and keeping an eye for broken skin in case of infection. Last years sore abdomen had Sudocrem put in it until the skin was healed, then the Udder Cream to keep the skin soft and supple. She is a much happier sheep this year. She is absolutely fine in the winter. My other Zwartble is completely unaffected. Hope this helps.