Do you think i can use chloraseptic for a canker sore?

Doubt it: If it is a true herpetic lesion, it is viral and will need to run it's course. Topical anesthetic may help short term

Yes: It will not harm you. It could help to control the pain from the sore due to it has an anesthetic in it. The sores will heal over time.

Canker sore: Canker sores (aphthous ulcers) run their course in 7-10 days. Applying a mouthwash can't hurt, but may not be of much help. Until it is no longer painful, Stay away from spicy foods and try not to irritate it. Get some Orabase Ointment OTC from the pharmacy. It is an oral bandage that will stick to the ulcer. Apply it before meals so you can eat without discomfort.