See the posting from AkainePSP labeled "Skin Issues". This will give you a good idea, 1st thing to do is get rid of all plastic bowls, etc. Not only do they hold bacteria, but they do put off chemicals and most dogs are sensitive to them. Don't worry it will go away. If it is real severe you may need antibotics from you vet. Read the attached reviews, theres alot of good advice in them.
Scarlet has dog acne,vet said from plastic water bowl. Heres the thread she was talking about http://www.bulldogbreeds.com/discuss/viewtopic.php?t=2965 and this is what Scarlet's looked like too. Bigger bumps around her chin and cheecks. Her chin was swollen somewhat. Hers was pretty bad and we got 6 weeks worth of antibiotics for it!
my vet said most likely water bowl but he said cause of the location of the bumps...It was definantly a contact allergy! Could be from food, grass, concrete...anything that touches that part of his skin. If it does not look like that it might not be serious...but Scarlets started off not that bad either...just keep and eye on it and look for him to be scratching/picking. At least Scarlet was...she opened them up and thats when it got bad.