Looks like bentgrass. It is a short, creeping grass and often produces flowers/seedheads at such a low height they are easily missed by mowers.

I don't know what part of the country you are in where you have a weed issue in a cool season grass in February. Having said that, are you sure it isn't just your bluegrass forming seed heads? Looks like that to me. Google KBG seed head and compare. It is common for KBG to form seed heads and is harmless. In any case, this would be a grassy weed if it isn't KBG and so the herbicide you have won't work. There are some fairly expensive products like Tenacity that are effective, over time, on grassy weeds, which are those that look like grass instead of the broad leaf weeds.

Maybe gardengal is correct, but it is hard to tell without seeing the whole plant.

Ok great. I looked them up and they do look the same. Im in nc and the weather has been in the upper 70s high 80s the last 2 weeks. The lawn was planted last october. Both with tall fescue and kbg. I will get a picture of the whole plant. But i think i are right in that it is the seed heads of the kbg

You have two identical threads going at the same time so it is a little confusing. Tom in the other thread said it is annual bluegrass, which is mostly poa annua. If you look up seed heads for poa annua you might find them to look thinner and more delicate than those for KBG, or poa pratensis. If you want to know for sure, look up "ligule" for poa annua and poa pratensis and how to tell them apart. There is a difference in how the little translucent membrane extends up in annua ve pratensis. Get a magnifying glass and take a look. It does look like just KBG to me from your photo, which is good news.