We just adopted a 4 month old puppy and he was treated with Frontline after his bath a couple of days ago by the foster mom. But when we picked him up Saturday, we noticed a couple of fleas on him. We want to treat now and have used your products before but cannot remember if Petcor is safe for a pup at this age (if size/breed matters, he’s an 18lb boxer/lab mix). I just don’t want him to suffer! Any suggestion would be helpful! Thanks!