Can my internet provider tell I used Tor Browser a week ago?
If they were looking for it, yes. Tor usage is quite obvious, and web browsers have a distinctive traffic pattern that can easily be told apart from something like gaming or streaming video.
Using a bridge to connect to Tor will hide your usage against casual surveillance, by making Tor traffic look somewhat like some other form of encrypted traffic. More advanced analysis will still reveal that you're using Tor.
If you didn't use bridges, your Internet provider can realize you were using Tor, but not exactly the Tor Browser, just Tor.
Everything over Tor is encrypted, so nobody except by the exit nodes can know what you browsed.
1Even the exit node knows that "someone" browsed it, not who. Dec 29, 2022 at 17:22