Maybe it's Mulescum Contagiosum. They look very similar to blisters, are sort of pearly, and have a little 'belly buttons' in the middle. They're viral infections and are harmless (but if they're on your feet they might hurt just from pressure...). When your body decides they want to get rid of they they sort of swell up and that's when they become VERY painful, espessilly if they're in place where there will be pressure of the. They can leak a little, especially when they're squeezed/scrathed/etc. Since they are viral they can spread via contact with other thigns, which might explain why he/she got them on hands too. They can scar and look like chicken pox cars. If they are painful try applying heat. You should definatly go see a doctor, because you never know what it might be.