G.L.
Hi L.,
When my daughter went through this I would fold one of her small washcloths and get the folded end wet and then put it in the freezer. After it froze she could chew on it and it was both cold and had some texture to rub on her gums. I only got the top half wet so the bottom part she was holding would stay dry for a while at least.
Good luck,
G.