Flat spot

My baby is 5 months old and I noticed a few weeks ago she has a flat spot. I know babies get them and they’ll correct themselves most the time but my mom is making a huge deal about it and telling me not to let her play on her gym mat anymore and is overall very worried about it. This isn’t a big deal right? You can barely see it but you can feel it. I don’t need to make an appointment to go in right? My mom is freaking out that she’s going to need a helmet 😂