Have you tried sticking a sanitary towel on your nickers over your scar or a panty liner.. my midwife advised me to stop the moisture Have a shower or bath wash it like normal let it completely air dry don't put anything on it -cream wise.
You need to keep it dry. You may want to get it looked at it it's inflamed and sore at this point. It should be getting better not worse.
My doctor told me to use volatrol gel on mine when it was sore (and suppositories for one week), but my external scar was glued rather than stitched. I also had some bodycon high waisted underwear which helped hold my belly tighter and relieved some pressure.