Leaf miners go after the bottom leaves as a rule. That doesn't mean you won't see one or two higher up on the plant, but that is usually few and far between. They will not attack flowers, and I consider them to be an inconvience, rather than something that will wreck your plant. If you want to you can nip the leaf off.

Of all the pests out there, leaf miners do very little damage to the leaf. Just the little tunnel they feed on. I've never seen swarms of them, just one or two here and there. I just ignore them. They eat very little, and as your plant grows it will leave them behind.

I'm only guessing here, but I think they originate as eggs in the soil. Once They are in their little tunnels I don't think they go up the plant. They mature and drop to the soil. By that time the plant has grown enough and they can't reach the new leaves so that means they must look for another seedling to mine.

You could spray them and kill them, but I don't want to spray my seedlings. In this case I think the cure is worse than the desease.

Just my $.02