Am I overreacting?

I told my mom explicitly many times to not kiss my baby (4 months old) for hygiene purposes and it also just grosses me out. I have many bad memories of her making me kiss her on the cheek and lips and it makes me feel so so gross because I didn’t feel like I had a choice when I was little (and I didn’t want to). She also used to tickle and bite me a lot, she literally chased me around the house and did this to me on her bed and I screamed for my brother to help me get away but my mom took it all as a big joke and didn’t stop until I was old enough to physically stop her. She is a school superintendent (for little kids) so I always figured she was right to do this to me (obviously she wasn’t).

As LO gets older I’ve stated noticing more concerning things she does. She seems to be getting more confident about her actions. Yesterday she was sitting with my baby and she kissed him on the top of his head. I was shocked and immediately said something like ‘you cannot kiss LO, you just kissed him’ and she said ‘no I didn’t’ and acted all surprised. She also started to poke and tickle him and when I told her to stop, she asked why, I explained (bc even though he’s a baby he probably does not enjoy that; he just can’t control his arms enough to swat her away) and she rolled her eyes and disagreed but she did stop.

How seriously should I take all of this? Am I just being an overly cautious FTM? She’s also made comments in front of me about biting his legs, and when I told her she can never do that she told my infant son that mommy needs to leave him alone with grandma for a while.

Up until these comments and kiss, she was our only trusted babysitter. But now I don’t want to leave LO alone with her anymore. Am I overreacting? Is a kiss on the head no big deal if LO Is already 4 months old/is this it’s normal grandma behavior?

She is amazing with LO otherwise, he smiles bigger when he sees her than when he sees me. He’s obsessed with her. These physical oversteps just started within the last week (he’s 4 months old) so I don’t know if he understands or cares.u