Question: how long does it take for a cold sore to form after exposure?
Answer: The first symptoms usually appear within 1 or 2 weeks—and as late as 3 weeks—after contact with an infected person. The lesions of herpes labialis usually last for 7 to 10 days, then begin to resolve. The virus may become latent, residing in the nerve cells, with recurrence at or near the original site.