Hello and thank you for contacting Petco Pet Education Center, formerly Petcoach. Unfortunately, it is very difficult to say what is going on from the attached pictures. It looks like some form of trauma or infected wound. You can try and clean it twice a day with 4% chlorhexidine solution (available at pharmacies). However, if the testicle is swollen or is painful to Batman, you should take him to your local vets for an appointment.