Help!!

So my dog gets SUPER excited when people come to my house like butt wiggling, jumping up, running all around excited, it is very very bad. I am so embarrassed to have people over. My grandpa has paper thin skin and she always cuts him all up and he doesn’t know how to handle her even though we have taught him many times but it still continues to happen. She is a one year old retriever mix and has a shock collar. She has taken training but she’s still bad. Any ideas?