A few things.
1) when you can tomatoes in their own juice, as tomatoes cook and make juice some bubbles appear. This is because the tomato tissue will release the air that was in the call tissue.
2) Sometimes the food was boiled so hard after being canned air becomes trapped in various places.
Botulism is the issue here. Just because a jar is sealed does not mean it will not spoil..
But if you put enough salt in the tomatoes when you were adding to the jars, there will likely not be a problem...
my mother always ran a butter knife down in the filled canning jars of tomatoes and salt
(salt is a preservative) to help any air bubbles escape.
IMO if you are concerned you could open the jars, use a knife or say a long spoon, to help the air to release and reprocess them with new flats.
1) I freeze all my tomaties.(so I am not a canner).
I measure a 15 oz can of cut up tomatoes and put them in a quart labeled freezer bag. Lie flat on a lipped cookie sheet in the freezer. When frozen I pile them into my chest freezer.
2) hopefully someone who is a proficient canner will come by and give you much more qualified advice.
Good luck !