Hello! Thanks for the clarification about peroxide verses dioxide! :>) So, your pubic area itched after a trim job and now if you get an itch there, it becomes a bigger problem with more itching? Is that what is going on? Really, it's going to be best if you go to a doctor to have the reason diagnosed. Is it contact dermatitis? Is it ezcema? Is it an allergy? A fungus? Each one has similar symptoms. Here's an article to look at. https://www.healthline.com/health/itchy-pubic-hair. Hydrogen peroxide or witch hazel will act as a mild astringent. This can help with ingrown hairs or issues like that. So, perhaps it is just that if it is getting better when you use the peroxide.
Correction: I have been using Peroxide not Dioxide