A sore that has been in your mouth for 2 or 3 weeks and has not healed should be checked by a professional. I would suggest following up with an ENT who is experienced with oral cancer.

The visilite will show abnormal cells. It doesnt necessarily mean they are cancerous cells, just that they are abnormal. The only way to tell for certain if the sore you have is cancerous is by having it biopsied.

Taking medication for 2 days isnt enough time to see if it works. keep using the medication, maybe it will help.

Even being young and a non smoker oral cancer still could unfortunately be a reality. The fastest growing segment of OC patients are younger and non smokers. HPV is now the leading cause of these young patients getting oral cancer. HPV+ oral cancer will appear in the base of tongue and tonsils. I would doubt this is your situation as your sores are on the side of your tongue. It sounds like something is irritating your mouth.

Get yourself checked out. Hope it turns out to be nothing serious!!!