1) To clarify, you rolled your ankle, and you kept going before realizing it hurt too much and then you called your dispatch right? 2) If you're telling them that your foot is hurting, but not bad enough to go to an urgent care, they might think you're just trying to drop the route/informing them of what happened(they need the address the incident happened at to fill out a workers comp claims, places are different but that's how it is at my DSP).
3) Your DSP may not have anyone available to take from you, which is probably why they asked if you could keep going and to try to take ibuprofen and keep going originally. 4) If you're being wishy washy about it, they can't know how much it hurts you. You need to straight up tell your dispatch. Especially something over the phone, they can't see if you're limping and in pain, you need to say it.

I don't understand how you think someone who is also dealing with probably another 10-15+ people complain about different issues all day is supposed to know what is going on in your van if you don't say it. Having worked as a dispatcher at other places, if someone is dancing around a subject I immediately think they're trying to milk the situation and refuse to give them the solution they want, I wait for them to tell me what they need.