I was viewing your page and I came across a symptom my cactus has become a victim to - rot. I was wondering, whilst looking through the directions of treatment, is it possible to just cut out the infected parts or must I cut the head off the plant and repot it? Thank you for your help.
It is hard for me to say given that I do not know the extent of your cactus rot. Depending on the nature of the rot you can either excise the diseased tissue by digging out the damaged flesh using a sharp sterile knife then allow the hole to dry out or you can take cuttings and root them (https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/propagating-cacti-and-succulents.htm).
For more information on cactus rot, please visit the following link: