Any rhetorical question in Sonnet 130?

In line 4, "why then" means "well, in that case." It's not a question. (If the line read "Are her snow white? No, they are dun," then the first half of that line would be a rhetorical question.) In line 13, "by heaven" means something along the lines of "I swear it's true." Again, not a question. (If the final couplet said something like "Yet how rare is my love? She is as rare/As any she belied with false compare," then line 13 would contain a rhetorical question.)