For a year after you should use a good sunscreen on the area. I had a surgi tape strip, so I didn't have any stiches outside, my scar was in the fold of my neck, barely visible.
you really to should avoid peroxide unless you dilute it. Peroxide will destroy the tissue. I am a nurse and I can tell you we no longer use that protocol. Most are cleaned with saline or a diluted mix of saline and peroxide but never undiluted. Avoid the salt water too. Neosporin is good to use after you clean the wound. There are many over the counter products can help reduce scarring. Check with your local pharmacist. Most scarring just fades into the natural folds of your neck.
a drop of mederma nightly will reduce the redness/scar out of it in a year
I've had two surgeries and they told me to put NOTHING on it for at least two weeks after the stitches are removed. The risk of infection is too high.
AFTER you have the stitches out, and then wait another two weeks, you can start using things like Vit E, or almond oil to help the scar become soft as the skin heals.