I can see there is swelling and some red rashes on his scrotal skin. It may happen for a couple of reasons.
1. Contact dermatitis - when the scrotal skin gets in contact with some irritable materials, then they will get these changes
2. Infection - Localized infection in that area or infection inside his system, which may result in symptoms like this.
So, in his case, we need to identify the root cause to treat it successfully.
Next Steps
Get a vet consultation for your pet to rule out the root cause and treat it
Health Tips
avoid all cleaning products that are not pet friendly