Simple past, past perfect,or past progressive tense:
Beth: hey Fred, what happened to your arm?
Fred: I was working in the garden and I had got my dirty. So I decided to turn on the water and clean up.
Beth: had you slipped and fallen?
Fred: Yes. When I was finishing dinner, my arm was hurting.
Beth: So what did you do?
Fred: I went to the hospital. By the time the doctor finally saw me, my arm had swelled.