I have gotton leaf miners in the past. Usually on adult plants but a few on seedlings. Try to trim/cut the bad blades with sharp scissors, but I have never had an infestation so bad it killed a plant. Sometimes I've let it go to harvest and never noticed a problem since they don't seem to hit the sugar leaves and we trim the fan leafs anyway. They are always a pain, and I get them on my regular tomato plants all the time - but the tomatos always come out fine, too!
My logic is to do the best I can manually, but I'd rather let a plant die (or get injured naturally) then have me screw sonething up and ruin it myself trying to help. Do a google search for remedies.