Breastfeeding help!

So baby was latching on first day. By day 2 lactation nurses said he was latching to high and only getting part of my nipple. My nipples were so tore up. Since i have borderline flat nipples they gave me a nipple shield so that I could heal. Now day 5 I'm trying to feed without the shield and get him to latch properly. but he's getting very frustrated with just my nipple. I think he's just used to the shield. Any advice on getting him to latch on my nipple again.