Can Tongue Piercing Cause Infection And Bad Taste?

Okay so, I got my tongue pierced almost a week ago and it hasn't caused me any problems. I wash it regularly with mouth wash and I noticed that it's been giving this awful taste in my mouth afterwards. Just recently though, behind my bottom lip, in front of my bottom teeth, I have this sore developing. It feels dry and rough sometimes, and it looks like it's a bit of a cut too. My tongue ring hasn't affected it because I can't put my tongue there. Is there anything I can do to make the sore go away? It's painful to move my mouth and very unpleasant.>Additional information : This is not a canker sore!