Is it possible to get lumps & sudden increase in size of lips &lumps 15 years after Artecol? Is there anything I can do?(photo)

I was happy with my lips although I developed a slight lump, top centre shortly after the injections but it wasnt really noticible. A couple of months ago my lips and the lump started looking bigger and a couple of small ones appeared. People keep asking if ive had work done but I havent had anything for 15 yrs! Im starting to get worried. The lump is noticable now and my lips look fake. Can problems occur aftersuch a long time? Anything i can do to reduce the lumps and prevent new ones?