What kind of riding thing? What type of saddle are you using? Western saddle, jumping saddle, or dressage?
If this is a trail ride and your ankle is not painful, you may be able to swing it if you aren’t putting a lot of pressure on it. That is, as opposed to a horse trial with two jumping phases where keeping your heel down is important.
It’s hard to say for certain though since we aren’t there to see it and most of us aren’t MD’s who could evaluate this.
My own opinion is that you are likely to have more trouble from dismounting than anything else. If you landed hard then you could end up doing more damage. Even more so if you landed and twisted your ankle in some odd way.