I had to look this up to be sure I knew what I was talking about, Renee, but here it is:
Lemon balm is Melissa officinalis and Lemon mint is Monarda citriodora. I was sure about the mint, not so sure about the balm. However they are all in the Lamiaceae family which means also that the mints sort of all look alike, but size and texture of foliage are a little different in each. Both are medicinal herbs though, or used to be. I can't remember the scent of the Lemon balm, but the scent of some of the monardas are minty but not as good as spearmint other more common mints. I don't like the monarda scent very much.
I love mints, Rita, and most spread including the Monardas (bee balm). The chocolate mint is low growing and I keep it in a tub shaped pot so that it doesn't spread. My other mints are everywhere, everywhere. . . . and that is what I've been doing all day long. Cutting back and pulling out wayward mint. I really do smell good!!