Ut forum is slow these days.
Your bath tecnique sounds fine and sounds like it worked out basicly fine.
Why not also give a try to JColeHaley's tecnique. He was certainly refreshed by using the fluid straight.
It seems unlikey your ankle pain is a crisis response from the fluid, but if it is, its info. (Along with sound and other frequency type treatments, easy, cheap and available castor oil packs, hot or cold are a great remedy for bruises and sprains).
Im always saddend a bit by people's stories of stretching injuries, partly cause my training was so specific on not forcing a stretch to gain a pose, or to just reallllly streeeetch using breath ect, but rather in learning how to allow and fall into natural relaxation in whatever limit of stretch is comfortable reached. Not too popular these days.