toddler mouth sore

Anaya 💙🧒🏻👶🏻👶🏻

My toddler has always got mouth sore inside his mouth never on his lip and today I noticed this

Iv talked to he’s doctor and he said they will just go away on it’s on.. but I’m asking all the parents on here if you have any remedies for this or any idea how we can get them to stop showing up