My 4 Yr Old Son Got Knocked Over By Another

My 4 yr old son got knocked over by another kid at the park. They were climbing up a concrete tunnel slide on their hands and knees. So it was a hard close "fall" to his forehead. Right in the middle. He's had a few bumps in his life. But they were all hard bumps. This one is squishy. Is that more concerning? Thank you in advance!