How long should I wait for steroid injection for scar tissue after Chin Revision?

chin revision from a medpor to a smaller sillicon. Semi soft lumps not going anywhere both sides of jawline after 4months. Went to couple doctors local and they all told me it's scar tissue. One saw my incision under the chin is pretty thick too and told me thats Y I also have internal scar lumps due to thick skin. Some says at least wait till 6months to do steroid while some says l can do it now. When should I do it? Any chance scar tissue wont respond to steroid?is surgical removal possible?