Kinda gross but what happened

Sorry if this is gross but what happened?? So last night my bf and I were making out and after he ate me out. After he kisses my arm and there was a little blood (like the tiniest amount). So I instantly panicked and thought maybe I just got my period but definitely not it then I looked in his mouth to see if maybe his gum or something was bleeding and there was nothing. His tongue had white stuff on it that he could scrape off(Ik absolutely gross). Which he didn’t notice until I told him. I instantly thought it was oral thrush but was very confused since I have 100% don’t have a yeast infection and don’t even think he could be got one that fast. So we ran out to get antiseptic mouthwash, probiotics etc. I was going to grab a yeast infection treatment for me but have had them before and know the feeling. The only possible thing that makes sense is that he just finished antibiotics (6 days ago) and possibly had the thrush then and just never noticed. He used the mouthwash twice and is mouth and now perfectly fine. We were kissing before we realized it and I am perfectly fine and also drank a lot of water to flush anything out. I’m still hesitant to kiss him but he looks perfectly fine! Has this happened to anyone?!