Is this puppy food allergies?

My puppy was on IAMS puppy food (chicken) when I got him. Around 11 weeks I tried switching him to Purina ProPlan Sensitive Stomach Salmon because he had some tear stains and I was wondering if it was food related. I very gradually switched to ProPlan but I noticed him scratching at his ears- they got dirtier- then these spots showed up not sure if they are related.

I have now switched him back to IAMS chicken and he’s not scratching anymore and his ears are looking better. Still have the tear stains though. I have wrinkle wipes and paste for them.

Should I keep trying to find a good food or leave him on IAMS? I guess he’s okay with chicken!