Although small bumps on both sides of the tongue are usually harmless, a bump on only one side may be cancerous. Unexplained red or white areas, sores, or lumps (particularly when hard) on the tongue—especially if painless—may be signs of cancer and should be examined by a doctor or dentist . Most oral cancers grow on the sides of the tongue or on the floor of the mouth
Read from the following link. hope this helps.
http://www.merck.com/mmhe/sec08/ch110/ch110c.html
Doctor
int.medicine board eligible, research fellowship cardiology.. working at UTMCK