Uhhh just to hijack a little - you gave him an aspirin? Was it a doggy aspirin? Or did you give him human aspirin? I just panic about this a little because giving human drugs to animals can have very bad, often fatal, side effects.
A basic guide for aspirin states, ` It can be toxic if given in high doses of about 30 mg per pound of the dog. This means that even baby aspirin could be poisonous for dogs weighing two pounds or less. An adult aspirin which is 320 mg. would be toxic for a 10-pound dog. To be sure that you are using the aspirin for the right reason and at the right dose, you should consult your veterinarian first.'
Sorry to jump in with that, I certainly don't mean to undermine your knowledge and I hope you aren't offended - but it just rings alarm bells...