Well, it may be a little too late for that, what with the pictures.
Hi, I called a few weeks ago about my cactus, attached are photos. I just moved from Richmond to Martinez and my cactus started turning a beautiful deep red color on one side but now it has a disturbing orange stripe down the center. Is it ok? Thank you in advance for your help.
Your Euphorbia looks like it has both sunburn/sun-stress and a fungal infection. The red is sun and the orange/brown/black is a sign of a fungus infection. I suggest spraying it with Neem Oil at 1 or 2%
solution. This will hopefully stop the infection. Spray to the point of run off, in the evening, not morning or afternoon as the oil can add to the sunburn. Respray after a week.