Minor blemishes like the OP don't bother me one whit, even if they happen on the first ride. Not to say I like large blemishes, especially if they're where I have to look at them. But a chain stay blemish would not bother me. BUT....
I got a titanium gravel bike so there's no worries about stuff like this
My previous "gravel" bike (re-worked cross bike) was very battle scarred and it was just fine. They should look like that after a while.