Do I have to pump right when baby gets a bottle?

I am going to a bridal shower tomorrow and taking my baby. I don’t have many options for what I can wear since I haven’t been shopping since before getting pregnant and I got rid of half my closet during a nesting frenzy lol. Basically my only option is a dress that is not bf friendly. I just know my baby is going to want to eat while we are there, even if I feed him right before leaving. He is 8 weeks old and since he sleeps really well at night, he feeds usually every 1.5-2.5 hours during the day.

With nursing and occasional bottle feeding, I was told to pump everytime baby gets a bottle. Do I have to pump right when he gets his bottle or could I just add in a pump session another time during the day? I’m considering taking a bottle for him to have at the shower instead of having to sit in a private room and basically fully undress to nurse him. He is 8 weeks old and I wouldn’t consider myself to be an over supplier, but more just an average supplier so I don’t want to negatively impact my supply if I don’t pump/nurse for 4 hours during the day.