Bump Below The Elbow, Near A Vein, Injured, Sore
Thanks for your query.
The blue swelling below the elbow after an injury is most likely a collection of blood in that localized area as a result of the injury. The collection of blood initially is red but later on becomes bluish in color due to degradation of blood inside it. Since your swelling has not got infected till now, it is most likely a harmless swelling.
Gradually it will resolve. For occasional pain or the draining sensation you can do cold sponging of that area.
While getting resolved the color will change to brown and then will be back to normal. Another option is that you can get the collected blood drained surgically if it does not resolve or if there are any pressure symptoms.
Hope I have answered your query. I will be available if you have any further queries.
Regards