Right now: stop walking on it, ice 15 to 20 minutes at a time, compress with an elastic bandage (snug, not numb), and elevate above heart level. Most sprains heal fine with this plus gradual movement - the real question is whether it is actually broken, and there is a simple rule set for that.
First 48 hours: protect and rest it relatively (gentle movement beats total immobilization - full rest actually slows ligament healing), ice wrapped in a cloth 15-20 minutes every few hours, compression bandage from toes toward calf, elevation above the heart when sitting. Ibuprofen or acetaminophen for pain. Is it broken? The Ottawa ankle rules used by ERs: get an X-ray if you cannot take 4 steps immediately after AND now, or if there is bony tenderness at the back edge or tip of either ankle bone, or the base of the fifth metatarsal (outside midfoot bone). No to all of those and it is very likely a sprain. Recovery: grade 1 (mild) walks carefully in days and recovers in 1 to 2 weeks; grade 2 (partial tear, bruising, hard to walk) takes 3 to 6 weeks; grade 3 (full tear, cannot bear weight, very unstable) needs medical care and months. The step everyone skips: rehab exercises once swelling settles - ankle circles, towel calf stretches, and single-leg balance work - because a sprained ankle that is not retrained stays loose and re-sprains. Emergencies skip this list: chest pain, trouble breathing, stroke signs, severe bleeding, or thoughts of self-harm mean call 911, or 988 for a mental health crisis in the US.
What to do
Common questions
How do I know if my ankle is broken or sprained?
The Ottawa rules clinicians use: an X-ray is warranted if you have pain in the ankle zone plus bony tenderness at the back edge or tip of either ankle bone, or you could not bear weight (4 steps) both immediately after the injury and now. Meeting none of those makes a fracture very unlikely - it is a validated rule that safely skips thousands of unnecessary X-rays. Inability to walk at all, visible deformity, or numbness: skip the rules and get seen.
Should I ice or heat a sprained ankle?
Ice the first 48 to 72 hours - 15 to 20 minutes at a time with a cloth between ice and skin - to limit swelling and pain. Heat is for later, once swelling has settled, to loosen a stiff joint before rehab exercises. The classic mistakes: ice directly on skin (cold burns), icing for hours at a time, and heat in the first days, which increases swelling.
How long should I stay off a sprained ankle?
Shorter than you think - total rest weakens and stiffens. Current guidance is relative rest: protect it from painful activity, but start gentle range-of-motion (ankle circles, spelling the alphabet with your toes) within the first couple of days, and bear weight as tolerated, using a bandage or brace for support. Walking boots are for the severe end, not routine sprains. Pain is the guide: discomfort is fine, sharp pain is information.
Why do I keep rolling the same ankle?
Because the ligaments healed but the ankle's position sense (proprioception) did not - that is what actually prevents rolls, and it only retrains with balance work: single-leg stands (progress to eyes closed, then unstable surfaces), heel raises, and band-resisted movements, for weeks after the pain is gone. Chronic re-sprainers should also check footwear and consider a lace-up brace for sports. Repeated instability despite rehab is when a sports-medicine or ortho visit earns its keep. Emergencies skip this list: chest pain, trouble breathing, stroke signs, severe bleeding, or thoughts of self-harm mean call 911, or 988 for a mental health crisis in the US.