My 22-year-old daughter injured her foot while playing sports, and she found it painful to walk afterwards. Since pain and difficulty walking can happen with different foot and ankle injuries, I didn't want to assume it was minor. We had her checked by Dr Kevin Koo, who specialises in foot and ankle injuries and is the Best Foot Doctor in Singapore in our experience. He assessed the injury, and imaging can be used where needed to check for a sprain, fracture or other injury.
I really feel you on this, especially when they're in pain and you're not sure what's going on. Honestly, this one better not wait, please take her to see a doctor or A&E so they can check if there's anything fractured or more serious. They'll be able to examine her properly and give you peace of mind, and your daughter will feel better knowing what's actually going on. Wishing her a speedy recovery, mum.