Morning
My wife had this problem for some time and the only treatment that healed them, after many attempts by other means, was homoeopathic treatment. I see many suggestions of topical applications, such as calendula and Manuka honey. I would strongly council against using these as it would appear, since the sores are not healing, that there is an underlying problem which has not been dealt with. This needs to be attended to FROM WITHIN OUTWARDS and not suppressed by topical applications. Homoeopathic treatment by a competent practitioner is, from personal experience, the best way to go. My wife's legs healed up within 2 weeks after obtaining the correct remedy.
Malcolm