You could try going to speak to the pharmacist at your local chemist. They may well be able to advise an over the counter product to ease the swelling and pain,Saves everyone time, and they can advise if MIU is more appropriate
Come on now you are just being daft. A pharmacist is there to help with have a got a cold or chest infection. No Pharmacist is going to start commenting on a leg injury.
OP you need to decide if its just a bit swollen and ouchy or if its potentially a bone or soft tissue injury.
Personally I wouldn’t an MIU. If you think its more than just a bump you need a proper knee examination, which either your GP or A&E can do. Also if you go near an MIU it will potentially need x-ray, and then review at hospital. No disrespect, but having been to MIU they have always diagnosed injuries incorrectly, and this is also the view of an orthopaedic surgeon