Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry to hear that your pups got into something they should not have.
Essentially these candy melts are white chocolate, and while they are high in sugar and fats they have very little to none of the toxins that typical chocolate has. The fact that they don't contain xylitol is great too.
The effects from this are somewhat dependent upon if your pups are used to eating table food or how sensitive their stomachs are.
They may have no effects, some mild nausea, or in rare cases this could stimulate a bout of pancreatitis (inflammation of the pancreas, increased digestive enzyme release, painful abdominal cramping, and vomiting), and you may see some loose stools.
They will probably drink more water than usual.
How are they feeling now?
How long has it been since they ate it?
To prevent stomach upset you might want to feed a bland diet for the next several days. And if they seem nauseous you can give an acid reducer.
You can give either:
1) Pepcid-ac (famotidine) at a dose of one half of a 10mg tablet per 10 to 20 pounds of body weight every 12 hours. (1/2 of the 10mg tab for the 10 pound, one 10mg tab for the 25 pound dog)
2) Prilosec (omeprazole) at a dose of one quarter of a 20mg tablet per 10 to 20 pounds of body weight every 24 hours. (1/4 of the 20mg tab for the 10 pound and 1/2 of the 20mg tab for the 25 pound dog)
Either of these will reduce stomach acid and should help settle their stomach. You can use these for several days if need be.
A homemade bland diet consists of 1/3 boiled, lean hamburger (or boiled, white, skinless chicken) and 2/3 boiled, white rice or pasta. Give small meals several times a day. Feed the bland diet for a few days and if they seem fine then start mixing in their regular diet and slowly convert them back.
Please let me know if you have any further questions.