Young lady.. while i understand your problem and empathise with you, perhaps a simple suggestion will be to avoid sanitary pads altogether and go in for a menstrual cup.
Do consult your Gynecologist to confirm and help you understand this better.
As for the Dermat issues that are persistent and peaky, please post some clear pics 📥 for privacy and do consider an Online Consultation and can perhaps guide you better towards a solution.
Ring-Guard etc are OTC products that are best not patronized.
Next Steps
Online Consultation
Health Tips
Avoid Sanitary pads or change more frequently to avoid friction
Use a gentle cleanser for the region and avoid 🧼 harsh soaps
Pigment lightening creams for sensitive areas as suggested by the Dermatologist you consult.