How long until my puppies worms are gone?

We got a new puppy today and we wormed her about 3 hours ago. I'm not sure if she does have worms but just checking. If she does, how long until the medicine has fully worked?

If you purchased an over the counter dewormer the answer is....it will not work at all.

She will need re-worming at least once, according to the schedule your vet recommends. In the meantime, you need to make sure she does not come into contact with her own stools (dispose of them promptly) so she does not reinfect herself. After that, she can still get them again if she walks in areas where infected dogs have defecated. So if she is around other dogs on a frequent basis, you should have a fecal exam done along with every annual vet check.