Something in cats neck

There was a heap of fur clumped up in our cat Links neck, at first we thought it wasn't very serious but after taking a closer look the fur roots were brown and red and crusty. We tried brushing it out but I am Afraid there is something in his skin causing irritation.
Here is a picture of after we brushed it out

Could it be an insect bite? Does it seem to have a "head"? Watch for signs of pus, particularly if it turns cloudy or yellow....that's the first sign of infection. If you have some Neosporin in the house dab a little on there (just a little).

flea bite maybe ? Or is it a different insect, and also I don't see signs of pus but there could have been before we brushed it out

That's a possibility. Do you have any other reason to suspect fleas? Does he spend time outdoors? Have you seen any dark flecks in his fur, particularly around the neck and shoulder? Is he spending more time biting or scratching than normal?

I gave him a flea treatment a week ago and cleaned up his usual areas he hangs out and no he doesn't go outside but I think it is a flea bite but I don't know where they're coming from I clean regularly

It's possible that it's a reaction to the flea treatment then. Some cats have an allergic reaction to the spot-type treatments.

Try putting a small amount of regular Neosporin on it to prevent infection, then monitor and see what happens. If you see more spots like this, get thee to the vet! 

Speaking from experience, that looks a lot like a botfly larva breathing hole. I recently took in a stray kitten - a 2lb ball of fluff - and just a few days aftewards, he had a spike of matted pus and/or blood on the side of his neck. He had been indoors the whole time, so it couldn't have been animal bite. I took him in to the vet, and when they shaved the area, they found a little larva glaring out at them. It took a while for the fur to grow back over the incision site, but he was back to his usual hyper-energetic self almost immediately after it was removed. He's much bigger now, but the vet techs all remember the tiny kitten with the horror worm in his neck.

Yikes...that sounds scary! Probably should get it checked then.

They showed me the larva - it was maybe... 5mm at that point? I declined when they offered to let me keep the vial it was in. I was lucky to catch it early when it had just erupted. Google images show that they get much, much bigger.