If it's just a few drops and maybe give it a day and if you continue to notice it take him to the vet. As for bulldogs I'd recommend you feed your bulldog a better quality food than purina puppy chow. One of the main ingredients of Purina is corn. Dogs aren't meant or designed to eat corn.
More importantly though you have an English Bulldog which are super sensitive to allergies and skin infections. I have an Old English Bulldogge which are supposed to be less problems because they are mixed with Pitbull, Am Bulldog and Mastiff. I can't give my dog any people food or ice cream or his stomach will break out in a rash and his feet will bother him. Same thing with cheap foods he'll react the same way. I feed my dog a Royal Canine dog food which he seems to like and react well to.
I don't recall where I heard this but remember some article or show quoting that the avg cost of ownership of a bulldog in vet fees is 5k a year. That seems high to me but I heard it somewhere. Even my dog I often have to go to the vet to get sprays for his skin or get him a shot of a steroid.
Buy the better dog food. It stinks it is much more expensive but it's healthier for your dog and may even wind up saving you in the long run by having a healthier dog. The Royal Canine I use is like $80 at the vet, however at Pet Smart it's only $57, plus you can normally find coupons online to save a bit more and another bonus I have a Capital One credit card and they often run a 35 point/mile per dollar spent.
You shoulda posted a picture of your puppy in your question I love bulldogs.
Just doing a quick google search found an interesting thread about this online. I know its only yahoo answers so not like vets or industry experts but the general consensus seems to be there's better stuff to food your dog than purina