3 year old, Suddenly walking on toes and side of foot

[jrobbins68]

On Sat. durring a family cook-out, my family and I noiced that my 3 year old daughter (will be 4 next month) walking with her right foot curving inward.  Since Saturday I have noticed she now is either walking on her toes on the right foot only, or on the side of her right foot while she still pulls her foot inward and it seems she is pulling in toes upward while doing this.  It is more noticable while she is without shoes.  She has not made any complaints about pain however when I specifically ask her if her foot hurts, she says yes.  When I ask where, she points to the ankle area, front to back.  There does seem to be some mild swelling on the outside of her ankle area, there is no discoloration or redness.

I am not aware of her having any specific injury to her foot or ankle.  However I do recall 3 weeks ago she was playing with the puppy and she said she twisted her ankle, cried for a few minuites, then like a typical 3 year old, was off playing again.

She has never had any problems with her development in walking, in toeing or walking on her toes before.  Since this has just started and not been an ongoing issue is there somethings else I should be looking for?  

Thanks for any assistance you can provide.