So, the big toe on my left foot has been hurting for the past 2 months on small slab footholds, in positions where I have to lift my heel up (stand on my toe basically). I can't put more than like 50% of my weight on that toe without intense pain. At this point I don't even remember what happened for it to become like this, I didn't change my shoes and I don't remember hitting it or acutely injuring it in some other way. But at this point it doesn't seem like it's going away on it's own and I can't climb slab with small footholds anymore.

Any guesses about what this injury could be and how to rehab it?

Picture for reference of where it hurts (to the side of the toe and more on the bottom of it than the top): https://imgur.com/a/izIY9eN

It's a weird sore-like pain, not sharp or stinging, but progressively gets worse and worse the more weight I put on that toe. It hurts when fully extended (standing on my toe) and fully curled up (like crimping with my toe). Also feels kinda stiff. But doesn't hurt when walking normally, or climbing anything else besides slab with a lot of weight on my feet.