Swelling down the leg - no heat, not lame?!

[UKa]

Hi, sorry, thought I'd start new thread from previous problem when horse was found with swollen hock after an afternoon of mad running about in field - since then I have kept her moving about and cold hosed the leg twice a day, there was no heat anymore since yesterday morning so thought I would just get the swelling to go down but this morning swelling has gone down into the leg, what does that mean? She is still not lame and there is no heat ...

 

[amandaco2]

most swellings will move down the leg due to gravity
(rather than an injury to the lower part of the leg)
alot of horses that knee the stable door can end up with swellings under the knee

 

[Worried1]

The exact same thing has happened to my horse. She had a lesson a week ago and then went out in the field where she had a sh*t fit! But no different to usual as she usually has a mad five minutes.
She then came in and her hock was swollen but there was no heat. So I cold hosed it and ice tighted it. Over the next 24 hours got bigger and having previously had a horse with OCD which presented as similar symptoms I took her to my vets. The flexion tested her and she was sound - they could not make her lame. They then x-rayed both hocks which showed nothing. They told me to go home and carry on as normal and ring if she got worse or went lame.
I bought some MSM gel and applied that to the area and began feeding her glucosamine but the hock continued to swell and the swelling spread down the outside of the leg, but there was never any heat.
I had a prod and a poke and found some little scabs so I washed the leg and hock in Hibbiscrub and telephoned the vets again. They said to stop applying the gel in case it was a localalised reaction to the gel and monitor it for a week. I also bought some magnetic wraps and began using them. Over the weekend the swelling has gone down slightly but the hock is still swollen. Exercise doesn't make it go dow or make it worse.
I am utterly baffled and so are my vets. They are certain it is not soft tissue damage as she is not lame or sore. The next step is a course of antibiotics and then if that fails to scan the hock.
But I'm in two minds do I just ignore it as it doesn't seem to bother her or do I continue to keep prodding and poking and end up with an answer I don't actually want?!?!?!?!?!?!?!?!