That's what people new to Dark Souls say about Dark Souls, not just Blighttown alone, which is the biggest*****hole ever, I hated it originally, it's much better in the Remaster without the 15 frames per 6 hours, but it's still a*****hole nonetheless

Late response but there is a way, thought it requires the use of a difficult to perform bug that might be patched already. There's a bug that let's you skip Queelag entirely, here's a video on how to perform it

Without exploiting whatever bug the previous respondent says exists, the answer is no. But you can kind of do both by joining the Chaos Servant covenant and feeding her sister humanity until she starts to feel better. That appears to be what Quelaag was doing, taking humanity from undead seeking the bell of awakening and giving it to her. If you can get your hands on the old witch's ring you'll be able to tell from her dialogue when the sister is feeling better. It might be at 30 humanity, when you reach rank 2 of the covenant. Though, I usually don't talk to her because she just thinks you're Quelaag and the things she says are SUPER SAD OMG NOW I'M CRYING WHY.

Fixed.