I have a potted (what I am 99 percent sure is) euphorbia trigona kept on my shady verandah though get a few hours of dappled sunlight each day.

The euphorbia has been neglected for quite awhile and I have noticed lately that it has some brown spots and dry scaley bits in the centre of the spots (the scales come off easily) and also what looks like scarring.

Any ideas what this is and how I should manage it?

Thanks very much!