I am finishing up my largest project to date - a lap blanket. Previously I’ve only done a few scarves. It looks pretty good for a new knitter I think - stockinette stitch with a border on the large size 50 needles with four strands of yarn so it’s taken me a while to do. 
Sadly, I’ve noticed that there is a large hole in the middle of it! I can’t tell if it’s a dropped stitch or maybe a yarn over. I really don’t want to tear it all out - that’s weeks of work for me, but I’m not sure I can live with the large hole in the middle. Is there a way to hide a hole in knitting? I’ve done some reading about the duplicate stitch - but that seemed more for darning holes coming from torn yarn and not blundered stitches…
Can you post a picture of the hole? A good close up would be best. That might help figure out how it got there and what might be done.
You’ll be able to tell the difference between a yarn over and a dropped stitch if you count your sts. A yarn over will increase the stitch count by one and a dropped stitch will decrease by one. If it’s a dropped stitch you’ll see a loose loop which needs to be secured so it doesn’t drop farther down. You could ladder it up as far as you can, then put a small piece of yarn through the loop and secure the ends in the adjoining sts.
Sounds more like you have an accidental yarn over. If the hole is too far from the cast off to ladder down to it (and with several strands of yarn used together this could be a nightmare) you could take one strand of your yarn and use it to sew up the hole, a stitch or two to close it up on the wrong side will make it much less noticeable.
Congrats on almost finishing your first large piece. Using several strands of yarn together is no easy feat!
Thanks for the replies - from the description above I think it’s a dropped stitch as I do seem to have extra yarn. As requested I’m posting a pic of the hole - and one that shows the ‘loop’. How I didn’t notice it until now is a mystery - I guess the throw is so large I kept it bundled up while knitting it and now that I’ve spread it out it’s an eye sore!
You might have gone the wrong way after putting the work down? With the textured yarn you should be able to close the hole up as salmonmac suggests and it will only show to you because you know where to look. Just make sure any loops are secured to keep it from running more. You’ll be good to go. Congrats on your large project!