Ear infections are caused by different strands of bacteria, sometimes the same medicine would not work. If you have not gone to your local GP for this infection then I suggest you do not auto-medicate (with prescription medicine) as evidently it does not work, and could threaten the effectiveness of the medication on bacteria that become resistant to it. If it does not get better within 2 days then I suggest you get an appointment with your local GP.
If you have recurring ear infections, then I suggest refraining from going underwater, while having a shower try and keep the ear dry, use some cotton wool dip it in Vaseline and put it in your ear enough to cover it before you shower.
Also worth mentioning: Typical ear medication contains antibiotics to kill bacteria and steroids to bring down inflammation. Steroids are known to have a lot of side effects, even if topically applied, if it not applied as directed by your doctor or applied for a longer period of time than needed. I seriously recommend you do not auto-medicate.