I don't know if it will delay a problem. As far as making it worse, if there is some injury that is being masked by the decca, I suppose you could risk further injury just by not feeling the pain. If the decca has actually healed the tendon, and thats why there is no pain... no problem. This is my first decca cycle, so I can't answer whether it is a temporrary fix or complete cure. As far as the location of the injections, it doesn't matter in my case. I shoot the glutes and was having trouble with the left achillies tendon.
Hope that helps, sorry I can't answer your question better.