Hi- I'm a dancer, and I had exactly the same problem when I accidentally stepped/landed on the outside of my foot. A sprain or a strain could indeed be the problem, and if you are doing things that cause it to hurt more, like walking on it, it IS likely to get worse and to take longer to heal.
Depending on the severity, it could theoretically be a problem with a tendon, which is what mine ended up turning into when I didn't stay off of it (it was a sprain at first, but the muscle weakness and continued use made it so that I hurt the tendon as well). Do be careful and rest it, since it ended up taking me a full 8 months to get all of y ankle strength back.
sagapou above had some great advice for how to deal with this- I'd just like to add in that an ACE bandage (or something like that) when it's wrapped properly, works really well as an ankle support, and it easy to adjust if it becomes uncomfortable in any way.
I hope you heal fast!
heyy bud yyour mom sounds like she knows what shes talking about ! it is probably swollen alittle bit aswell if you compare it to your other ankle.. i would recomend you stay off it for abit i actually have a simliar promblem to you at the moment exept on the inside of the ankle.. it is very tender wen you touch it it feels sore.. the best advic for you is to stay off it if it is very bad an ankle sprain can take up to 2 months to heal fully although from what your describing it does sound bad but hopefuly not that bad.. i would do 20 minutes ice (although this is better when you first injure it ) give a 20 min break and use 20 min heat ! that should help aswell as lots of rest do elevate it stay off it the body will naturaly heal over time i recomend you look into arnica gel and or arnica pills they are natural herbal remedies which will help you as well as look to get some ankle supports to wear on your foot to keep the structure ! goodluck bud hope that hellps