Frequent Swelling In Lower Back Since Epidural Blood Patch And Spinal Tap. What Is The Cause?

hi, i had a spinal tap done in early september followed by a epidural blood patch. since then i have had swelling that appears quit often in my lower back. the swelling is where the back indents right above the tail bone area. when it swells it is painful and i get sharp pains throughout my lower back. im finding it hard to be on my feet for lengthly periods of time and certain ways i sit or lay down will also affect it. should i be concerned? and what could this be?