I do not have the answer, but I have had a similar problem that got much better after taking vitamins like omega 6, omega 3, folic acid, B6 and B12.
I researched the skin rash to a type of eczema which is apparently connected to a deficiency of omega 6 among other things.
Hi,
This may be a case of folliculitis or a fungal infection. Folliculitis refers to a skin infection caused by Staphyloccocus aureus, a skin bacteria. Shaving may increase the risk for folliculitis. Any minor cuts on the skin may increase the risk for colonization and infection by this bacteria.
A fungal infection may present with redness, itchiness and scaling of the area. You may need topical antibiotics or antifungals. Treating the underlying problem such as an infection shall prevent spread of the condition and also prevent further recurrence in the future.