Oh, poor little Pug!!
What you are describing at the moment with lumps all over his body sounds like he may have HIVES. This is an allergic reaction that causes these swellings. It can be to an insect sting, a spider bite, or to a medication.
When I see dogs with this, I treat them with BENADRYL (diphenhydramine).
The dose that one generally gives is 1-2mg/lb.
It comes as 25 mg tablets, and if he is 18lbs, if he were my patient, I would give one full 25mg tablet immediately. This can be repeated every 8 hours for 24-36h.
Here is more about Benadryl:
You should see improvement within 30 minutes.
In the meantime, apply cool compresses (a small towel dipped in cold water and wrung out) to the affected areas.
Here is more about allergic reactions in dogs:
If the swelling is increasing in size or starting to include other areas such as around his face or nose, I suggest you take him to your veterinarian immediately.
***Please stay with him until it starts to come down because if it starts to cause swelling in his airways this could be serious.****
If it comes down with the Benadryl, it raises the index of suspicion that this is an allergic reaction.
I hope that this has answered your question about your Pug's skin bumps.
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If you need more information, just click on reply and I will still be here to provide it!
The above is given for information only. Although I am a licensed veterinarian, I cannot legally prescribe medicines or diagnose your pet's condition without performing a physical exam. If you have concerns about your pet I would strongly advise contacting your regular veterinarian.
Good luck, Fiona