tattoo swollen after 3 months

I had a tattoo done in Feb of this year....its a sphere with tribal design in it. It healed nicely until about beginning of April. The colors are red and blue. The red got swollen and really puffy and hard. It didnt hurt at all but got really swollen. I work for the railway and was figuring it was coming from the creasote in the rail ties. The red color is getting really dry and i put vit E on it. The swelling goes down and then starts back up again. Any help is greatly appreciated. I think im going to see my doctor soon. Thanks DIMEBAGZ