I think we have our first sickness..or teeth

Scarlett went to bed last night fairly cranky. I think she’s teething, because she was crying and making an mmmmm sound with it. Which is new! She woke up this morning fine, I kissed her goodbye and she felt fine no warmth. My husband left about an hour after me, kissed her goodbye and noticed she get warm. She acted normal throughout the day, ate and drank normally. But woke up from her nap and my MIL said she was burning up! And when she changed her diaper, she pulled her leg out of her pants and she was whining a little. I got home about 20 minutes after, and her face was bright red, cheeks even more red, she felt hot. But when I took her temp, it was reading 98.9. I used a forehead thermometer, but may try rectal or armpit in a little. She’s acting normal. She’s just hot and her face is very red.