I think I neglected my coral cactus and it now has dry brown spots all over the fanned part. Will it recover if I water it regularly from now on, or do I need to cut out the brown spots or cut anything off.
The brown patches are caused by root damage due to improper watering. Unfortunately, damaged plant tissue never recovers. However, the spots are not a disease and are not likely to spread if you get the watering under control. Cutting out the spots will not accomplish anything except to make your Coral cactus look like Swiss cheese! So, I’m afraid you are going to have to live with the way it is now looking.
Proper watering is challenging when a Coral Cactus is potted the way that yours is. The layer of pebbles on the surface look very pretty, but they prevent you from properly assessing the dryness of the soil around the roots. In addition, if the bottom of the planter has no drain hole, then water may collect in the bottom and cause root rot.