Brief Answer:
You might need oral antibiotics and sitz bath

Detailed Answer:
Hi dear,

Welcome to healthcaremagic.com.

I can understand your problem

In my opinion the condition might be due to excessive friction caused by riding bike.
using local antiseptic is the first home remedy.

I am very happy to know that you are taking proper care of wound locally.
As the wound is not subsiding its advisable to go for some oral antibiotics. The area near anus will be very rich in different bacteria that might cause non healing of the wound.
Considering your age as a factor its better to rule of any chance of diabetes.
Diabetes is one more reason for non healing wounds.
The best approach is consider taking a culture sample and start antibiotics as per the culture and sensitivity report. The wound care and wound analysis is best done by surgeons.
I suggest you to see a surgeon and consider taking antibiotics.

Mild pan killers like panadol can be used for temporary pain relief.
kindly let me know in case of any further query

Regards.

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