I did that like 2 or 3 times but it wasn't working, I don't know what happened but after I summoned the ship, and then the day after went to sleep earlier, it worked. BTW, do you know if there's a way to purge corruption of a demon that beat you many times but still isn't in the emblem? I screwed up my timing after injecting the syringe to Rose (goddamit, she only had, literally, 76 hp left after my attack, she survived by her teeth skin and used her gaze) and now she just activated her gaze at the start of the battle without letting me do anything, what I can do if I want to beat her properly?
It's specially frustrating since I followed the rules, I watched the top of her hp bar to check when I had to do evasive posture, defensive posture, etc. resisted until she let her guard dow, injected her, and since I had my gym buffs maxed up I was so OP that I depleted her hp in just 2 attacks with only 76hp left and then she fucked me up permanently because some minimal error at the end.... what can I do so that I don't restart the whole fucking chapter 2 from zero because of that?...