Is this a major foot injury or just a bruise or soreness?

I was coming down the stairs and stepped on my mom's high heels, toppled side to side and landed (basically I tripped over them). Right afterwards, I iced it for a while, went to bed, because it hurt on the side of my right foot. It felt a little better the next day, my mom put some chinese medicine thing on it. This is the 3rd day. Now, it doesn't hurt if I walk on carpet, but on hard wood, it hurts during the parts when I walk with pressure on the front/side. Is this just bruising or is this some sort of major injury that should be treated? My mom wanted me to go to tennis tonight but I'm not so sure...what should I do?

You should rest and stay off your feet. It is most likely a ligament sprain, and is still sore, as exacerbated by the pressure of walking on an uncushion floor. So, no tennis tonight.

Initiate RICE therapy technique (Mnemonic: RICE-M)

Relative Rest
Ice
Compression [Apply elastic bandage if needed]
Elevation [Elevate extremity 15 to 25 cm above heart level]
Motion [reduce movement, helps to decreases edema and hematoma (bruises) & assists healing]

Also avoid those chinese medicine that makes your foot hot (ie. foot rubs, like tiger balms or Eagle brand Green ointment)

2-3 days of rest and you'll be ready to play tennis again without worry of a repeat injury.

Sounds to me like it's just a bruise - maybe a deep bone bruise. Those are painful but you'll be fine. As for tennis tonight that's up to you - if you feel up to it I guess you could play, but I would say that would only make the healing process take longer. If I were you, I would ice it, keep it elevated, and stay off of it as much as possible.

just let it get some air. or just do what i say:

take some sand and fry it without any oil. when warm, just try wrap it aroung the affected area using some cloth or psper. it would help and relieve better and make heal fater.