it is difficult for me to assess the scar based on a picture alone, without any examination.
It appears from what you’ve described to more likely be a hypertrophic and hypopigmented scar – which may be treated with steroid injections, or surgery. Bear in mind that any surgery of course carries a risk of an even worse scar!
Silocone sheets are indeed one of the methods to treat these scars, but are usually much more effective at prevention, or when it’s used at the early stages of a wound/scar.
You can check out this link for more info about hypertrophic scars and treatments:
http://www.aafp.org/afp/2009/0801/p253.html
Once again, it’s really not ideal to recommend any sort of treatment for a scar without examining it in person – the best advise would be to visit a doctor in person to have it checked out.
Cheers