How can i tell the difference between oral herpes and canker sores?

Location and appeara: Herpetic lesions occur on the lip borders. And are usually solitary lesionsprimary herpes can occur in multiple oral locations and this one time event can be associated w/ fever, malaise, and mouth pain. Herpetic lesions start out like a pimple which then bursts and becomes crater like, with a slimy exudate, canker sores are on oral mucosa, are red w a white ring, and don't have the exudate.