What kind of medication did you put into your tank? Your tank needs to be at least 2.5 gallons, and if you are going to use meds, there must be some sort of filtration or aeration system, otherwise your betta could suffocate. The safest bacterial remedy is MelaFx- at PetsMart- and follow the directions exactly. Also, feed your betta a medicated fish food to help his immune system. If you have plastic plants in your setup- take them out. They are too abrasive for your fish, and so those red streaks could be from the betta rubbing his face against the plants. Plastic plants remove the slime coat and creat abraisons on the fish, leading to bacterial infections. Switch to silk or live plants. Test your water and make sure that he has the best water quality possible. You can call any PetsMart, ask for the specialty dept manager, and that person can tell you more about what could be wrong with your betta.