Chuck a picture(PrtSc) up mate so we can see what you mean. Without a pic I will guess...you have merged multiple verts?? in one go?? If you have go to these and change the thresh hold. If I am right it will be merging verts that shouldnt be...checked your vert count if you have it up in the HUD or and go X-ray to see what funkiness you have happening.

cheers bullet