Mamas I need advice !!!!

So my LO pooped in his sleep the other night and I didn't know it until morning when I changed his diaper . The next day I noticed he was developing a little bit of a rash so I let him air out , then I put desiten on it . That didn't help  . So I tried just letting him air out and gave him oatmeal baths , and made a paste with breast milk and corn starch and that seemed to help . It started looking better but then yesterday we had several runny diapers (that went up his back ) so I continued using the cornstarch and breast milk .. We'll then this morning we woke up to a horrible horrible rash that completely covers his little bottom . His doctor couldn't see him today , but suggested leaving a diaper off of him . That worked until he started clawing at it an now it's oozing stuff and is really raw . He has an appointment in the morning ! However as a mom , I'm freaking out because well that's my job to worry I guess ! It's splotchy looking , and now it's spread to his little peepee area ! Does this look like yeast ??​