Quoting Becky☮Will:" I wouldnt try that unless you absolutely need to. I have heard girls on here talk about it actually messing up their LOs latch even worse and never being able to breastfeed normally again "
Definitely dont do the nipple shield. It causes confusion. I was forced to use it and now LO refuses my nipple. The LC told me that it will probably take over a month to wean him off of it. My nips are bruised and beaten even with the nipple shield.
If you absolutely need to, talk to an LC about getting an SNS feeder. You might be able to hold the tube next to your nipple and let your LO get formula and breastmilk at the same time.