Is there something that can be done about rugs seams?

We just moved into a house with berber type carpet. Where the carpet meets other carpet(not the wall or other flooring) I have noticed the seams look ragged. Like they are separating is there something that can be done, some seam tape. Carpet replacement is not a current option. I am also not sure about lifting up the carpet to re-tape it, I would be afraid of messing it up more. Is there any of those wonder products that might help, I was just watching a tv infomercial and thought hmmmm.