I can completley relate to dental pain and how awful it is! Teething gel provides mild temporary relief and the clove thing actually works! I also found the rinsing with salt water helps a little but the best thing was to actually hold an ice pack on the outside of me jaw (in line with the sight of pain) as you would for a sprain (20 min on, 20 min off. Or whatever you can handle). When my WT were bad I had this ritual of salt water rinse, gel, ice and then as the gel faded, clove and kept alternating.

If your chemist was unhelpful, try a different one. Go to one where there are a lot of pregnant women in the area as they tend to be a little more aware of what is safe (it's in their best interest if they want to keep their customers!). Perhaps ring a couple of chemists to get different opinions.