Is it some kind of allergy?

Our cat is almost 8 months now. Last month we gave him this medicine recommended by vet. After that his hairs gone weaker from both side as in attach pic.

That time I went to vet, and he said it's nothing problem these hair will grow again and its not any infection. But still after one month nothing change.

He is on vaccination, his 3rd and last vaccine is left. I want know some one know about it? Is it some food allergy or something? We give wet food of whiskas brand.

Thank you

I'm sorry to hear this is still going on.  I remember when you first posted about his hair loss but I think, based on this picture, I might not have realized what hair was disappearing.  You're talking about the thin patch between his eyes and ears, right? Cats do tend to have thinner hair in that spot, but this is less hair than usual.   I actually had a cat once who looked just like yours.  My cat already had the thin hair when I adopted him and when I asked the rescue group if I should worry about it, they never answered me.  He was almost bald between eyes and ears.   His hair never grew back and I never figured out why it was so thin, but it didn't seem to affect him.  He was very healthy.   I had him before I knew about food allergies so that never occurred to me - he ate Friskies, which I've since learned is not a highly recommended cat food.

Whiskas is like Friskies.  It's not considered to be one of the better canned foods.  If you want to try a different brand to see if he has a food allergy, the following might help you choose.

http://www.thecatsite.com/a/how-to-choose-the-right-food-for-your-cat

http://www.thecatsite.com/a/what-makes-the-best-canned-cat-food

http://www.thecatsite.com/a/best-cat-food-of-2015-tcs-member-choices

I'm afraid I'm not much help here.  I don't know what causes the hair loss but can only reassure you that if it's the same as my cat had, it doesn't seem to be associated with other health issues.   

As kittens transition into adulthood, their hair thins in that spot on their head.  I have 4 cats and they each have a different amount of hair in that spot.  My little tortie girl has the thinnest hair in that spot.  At certain angles, she looks almost bald. 

Wurp is like this, very thin there, almost bald. I had Shortstack neutered 2/5/16, and now he is losing his chubby cheeks and his hair is thinning in the same spots. I was beginning to think it was associated with neutering, but reaching adulthood pegs the timing on Wurp's hair loss. I have pics of him when he was young and his fur was very thick there

Thank you every one to consider it. Actually, this cat is first pet in my life and don't know much about cats. That's why I am worry that this normal or particularly some allergy.
I think its normal as you lovely kitten also suffer this. But it seem not good.

Unfortunately in our country Saudi Arabia these brands are available for food. Whiskas and Friskies.

Another unfortunate is I am job less since four months. Can't afford to buy online.

Anyway thanks guys.