Does oral herpes inside the mouth look like canker sores at all?

Once the blisters: of herpes have popped it can slightly resemble a canker sore

Not herpes: If INSIDE the mouth it is almost certainly not herpes. Most likely aphthous stomatitis.

Sometimes, but...: Individual herpetic sores in the mouth can look like cankers, but the overall picture is very different. Herpes in the mouth almost always is the first HSV infection, usually with multiple sores, severe sore throat, often blisters/sores on the lips at the same time, and systemic symptoms like fever and headache. If 1-2 sores in the mouth and no other symptoms, almost certainly cankers not herpes.