My friends dog's used to fall off cause he had allergies and would scratch and they would come off, but there was usually blood from him scratching them off, but if there's no blood or scabs or anything and they're just falling off by themselves talk to a vet! Good luck! Hope he's ok!
No, nothing is wrong- they just come off every once in a while. I usually grab my dogs (shih tzus, if I don't do this, their hair stands out funny, lol) whiskers to cut them off, but sometimes when I isolate the whisker, it simply falls off.
My guess is whiskers are shed regularly so as to replace them in case they are cut, bent or broken.
I should think that like in humans, dogs hair will fall out and grow back, if he had some sort of skin abnormality or was showing signs of illness then i would be worried .
Keep an eye on the situation and see if it worsens.
I hope that your dog is ok.
Good Luck x