How do you tell if a fever is due to unrelated virus or if it’s from an infection of fissure?

I’m Female 30 and work with 5 year olds. I’ve had a fissure on and off for 7 months. Pain when going to bathroom and red blood and soreness after. I use sitz bath , aquaphor and balenol lotion. It’s been flaring up the last month or so after a calm era. The pain itself doesn’t feel dramatically different from my normal fissure flare, just more irritated from loose stools.

At the same time, I got a fever that looks very viral: • Sudden onset • Fever breaks in the morning • Comes back in the afternoon • Responds to Tylenol • No lump, swelling, redness, or throbbing pain • Pain is NOT constant — mainly after pooping or stretching the area

I’m trying to understand from people who’ve had fissures: Have you ever had a fever caused by an infected fissure? How did you know? And did your symptoms look different from a normal viral fever? I’m on day 3 of fever 101.8 is the highest I’ve seen since first day, I went to urgent care and was negative for flu and Covid but didn’t tell about my fissure.

I just want to know what the true signs of a fissure infection or abscess were for you, and what helped you realize it was something more serious vs. just the fissure flaring and a virus happening at the same time.