I Have Been On Depo Shot For 4 Months ,

I have been on depo shot for 4 months , In may on the 14th I suppose to went in for the second shot but instead I missed the due date and made another appointment for the 29th. Every since last week and the following weeks I stopped bleeding and two days ago I noticed down below I had inflammation burning whenever I touch against it or wearing clothing. But my discharge changes throughout my menstrual cycle but the next day it went to white/clear to a slight yellow until that day I have been taking baths in baking soda to get rid of the smell and color. I need help to figure out what is causing it to happen, I haven't had bv for a while which was last year in november .