SMZ TMP DS

Okay so Im not sure if this is a side affect or not. But after taking this medicine I had a lot of tiny sores you normally get in your mouth from time to time, on the inside of my lip(bottom). There's no sores on the outside just tons of little ones in one spot at the bottom of my lip that hurt really bad. Along with extremely chapped dried lips. I don't drink any acid liquids in fact I was drinking two big glasses of water a day I missed out on a day because of various reasons my lips were just chapped. So the next day i drink three to four large glasses of water and things just get worse. Im not sure what the deal is but I stopped taking the medication. Im not sure yet if it'll get better. But do you think me taking SMZ/TMP DS is the cause for this?