MRSA vs pimple vs something else

My son has a pimple on his hand that showed up sometime today. The baby sitter pointed it out when I picked him up. I initially didn’t think much about it then started to worry bc we went to the hospital over the weekend to see my husbands mom. So now I’m worrying. He isn’t bothered by it or messing with it. This is what it looks like..excuse my faucet..I’m guessing we have hard water and can’t get it to look clean. I’d take suggestions about that too tho lol

I should add he is in a in home daycare and her only kid but she has an elderly mom she cares for too.