Hello, my name is***** and I have over 20 years of experience as a veterinarian. I understand that you are concerned that your pup just ingested a condom.
It may pass but because these are undigestible and he is a small dog, if has been less than 2-3 hours since he has eaten the condom, I think it's worth trying to get him to vomit it back up.
You can give him 1 tablespoon of 3% hydrogen peroxide per 10 pounds of body weight soaked up with bread chunks, or mixed with ice cream or a little dog food (no more than 3 tablespoons of peroxide at a time even for a pup greater than 35 pounds).
Then take him outside and run him around to get the peroxide bubbling so he vomits.
If no vomiting in 10 minutes repeat the peroxide dose once.
If he vomits and seems to clear his stomach and be done I would check to see if the condom is present.
Once he clears his stomach to try and settle his stomach today you can give either:
1) Pepcid-ac (famotidine) at a dose of one half of 10mg tablet per 10 to 20 pounds of body weight every 12 hours.
2) Prilosec (omeprazole) at a dose of one quarter of a 20mg tablet per 10 to 20 pounds of body weight every 24 hours.
These will reduce stomach acid and should help settle his stomach.
Then feed a homemade diet of 1/3 boiled, lean hamburger or boiled, white, skinless chicken, all fats and juices drained off the meat, and 2/3 white rice. Add 1 tablespoons of canned pumpkin, (not pie filling, just pumpkin), to each meal for fiber whether he vomits the foreign material or not to help push any remaining pieces through.
If you don't have peroxide or he doesn't vomit you can get him to an emergency clinic to induce vomiting.
If it has been longer than 3 hours it is likely too late to induce vomiting, then just feed him the bland diet mix and watch him for signs of an obstruction.
If he doesn't vomit the condom and he starts vomiting in the next few days, has a tense painful belly or refuses to eat or runs a fever (more than 103F rectally) then that can signify a blockage and he should be seen by a veterinarian immediately. Surgery may be needed at that point.
Please let me know if you have any further questions.