Thanks for posting your query.
Surgical scar healing may take long time in some patients and it may be caused by poor nutrition, stress, contamination of wound, infections, diabetes
You can speed up healing by taking proper diet, vitamin c
supplements/ orange juice, zinc supplements. Keeping the wound clean and proper regular dressing can also help wound healing
Known and frequent side effect of silver nitrate
sticks is skin discolouration and pigmentation. Avoid its long term use.
If problem persists then contact your treating doctor for further management.
Hope it helps.