Maple bow advice

[Nightmyth]

Last night I noticed my bow had a  slightly dark discoloration patch on the back, about 10"  from the tip. I could only see it when I looked at the bows back at a shallow angle against the light. When I ran my fingers over the patch I could feel the area was a little rougher than the rest of the bows back. Clearly I can tell the fibers are starting to raise.

The bow is tillered so far to, 40-45 LB @ 20".
The final goal is 45-50# @ 28" after silk backing and snake skins are applied

My question is. Should I add the silk backing now, and continue tillering after to be on the safe side? Or do I continue to tiller, and not over stress the bow, then back it when I reach my 45# target?

Lastly this is my 3rd bow. I apologize if I didn't provide the right info.

Bow info: Maple Board short bow ( can provide dim/pic if needed)

Myth

[leapingbare]

I would go ahead and add the silk if your worried about it. i have never worked with silk but when i sinew back bows i Floor tiller the bow and then I run a line of sinew down the bow before i really start to tiller it at all.
   leapingbare.

[Nightmyth]

Yeah I'm a bit concerned. Sounds like its ok to back then tiller. I think I'll be cautious and do that then, thanks for your input Leapingbare. 

[1/2primitive]

Back it now, for sure. In fact, since silk and other cloths are for safety, not for strength, it's a good idea to back the bow before you start tillering. I had a bow that had a clearly visible crack in one limb that held together for a while with just a linen backing. btw, I took it apart, it didn't break.
    Sean