Looks like traumatic episcleritis. This redness will subside with a short course of topical steroids, but more importantly, the eye has to be examined under magnification for evidence of any other vision threatening injury. Therefore, it's better u consult an ophthalmologist. Gentamycin is not going to help.. pls stop it immediately.
Next Steps
Consult an ophthalmologist in person, if not possible then try online consultation.