Again!! This seems to be about once a month now. The little fella is always coming home with a lousy head. The bloody lotion stinks the house out, and, of course, it's dads job 
Our girls kept coming home with them got really annoyed.
Mrs tried everything but she was told about using Listerine Mouth Wash the blue one, Cool Mint.
She bought an empty spray bottle, and put undiluted mouthwash in it, sprayed it on the head soaking the scalp, put a shower cap on, as that heats it up, letting it dry into the hair.
When its dry rinse with warm water then comb through with a "Nitty Gritty Comb".
The combs are dear but well worth the money, you can get them off ebay or Asda Pharmacy sell them at about £9.99 but they are brilliant

After using this mouthwash you should find the Nits are all dead, the Nitty Gritty Comb pulls the eggs out.
You can then make up a weak solution of mouthwash and water spraying it on every other day, this should stop getting them again.
Hope this helps