Wrist injury ? RSI ? Tendinopathy?

Hi all, I've got a wrist injury and I'm having trouble diagnosing it. Let me give you the history and if you've got any suggestions please share!

I'm an athlete and my conditioning training involves olympic weightlifting and exercises like pull ups and things on the gymnastics rings.

Gradual onset 3/52

Pain on passive EOR wrist extension
Pain catching the bar in the front rack position

Rx: RICE

Pain subsided but was then re-started during a muscle-up on a bar (pull up into a dip).

Local tenderness around flexor retinaculum (no neurological symptoms)

There's noticeable swelling at the distal end of the forearm around the tendons and on palpation it feels noticeably different to the other wrist.
When I clench my fist the tendons look a lot thicker than the other side.

At rest pain is 0/10

I've been taping my wrist to limit extension which helps a lot and I can still train but it gets progressively more sore until I need to stop.

I've been doing simple eccentric wrist flexor exercises with a resistance band but I'm just assuming it's a tendinosis type injury at the moment.

Can anyone help me out?

Many thanks

Which hand? And exactly where is the swelling? Dorsum or ulnar/radial side?

Sounds like a problem with the synovial sheath. Some form of synovitis or synovial cyst. Can't tell based on the description of the swelling alone.

Attachment 1068Attachment 1069

Picture on the right is my right hand and the injured one. Swelling is literally right down the middle (I think maybe along the palmaris longus tendon?)
What do you think?