How are the white patches on his fins and his mouth? Were the white patches like dots of salt or were they fuzzy? What other stuff besides ich medication did the put in his tank? Putting the tap water in with water conditioner (declorinator) was a good move. You can do another 50% water change tommorow. Keeping his water clean will help him heal regardless of what is the matter.
This is what was wrong with his eyes but that sounds like it's going away:
•Symptoms: One or both eyes will swell and bulge out. It in itself can also be a symptom of Dropsy.
•Treatment: Usually not fatal if treated, but your betta might lose an eye. Conservative: If the swelling is extreme then use ES first. Perform 100% daily water changes. You may be able to treat the popeye with just Epsom and clean water. However, if the swelling goes down but the eyes remain cloudy/white, then switch to Aq.Salt at 1tsp/gal or use medications. Do not combine Aq.Salt with medications but you can continue to use ES during medical treatments. Medication: If ES or Aq.Salt do not do the trick or it is a serious case of popeye, then combine the ES with API Tetracycline, API Fungus Cure, API General Cure, API Triple Sulfa, OR Mardel’s Maracyn.
I am going to give you a link that has a good chart for diagnosing fish diseases. This is to better help you describe what condition he is now not necessarily to run and get more medicine yet.