Im doing an 8 week arm workout and I have been lifting my arms every day now for 5 weeks with little signs of change. Is it possible that im lifting the same muscles too much? I heard you should do it just once a week.
Definitely overtraining. I don't know where you got that routine from, but it's not something anyone should follow if they want results.
At the same time, eight weeks is not enough to see results, even when you're on a good program- This sort of thing takes time and patience, and a lot of dedication-
For example, the dedication to eat five or six meals a day, putting more calories into your body than your body actually needs- It's those excess calories that muscle is made of. Without those, no routine is going to get you big arms, period.
You'll also need the dedication to work ALL of your muscle groups- Not just your arms. Even if you're only interested in getting big arms- Or just muscular ones- You really need to work every muscle group to get the best possible results. Someone with ripped arms and skinny legs just looks ridiculous. Besides, training all the other muscle groups- Chest, shoulders, legs, back and abs- Greatly increases the gains in your arms anyway.
So work your arms only once or twice a week, with a routine something like this-
Biceps-
Standing barbell curls
alternating dumbbell curls
Reverse curls
Triceps-
Close grip bench press
Skullcrushers
triceps pressdowns
three sets of each, six to eight reps or so each set- And you should see nice results, provided you're eating right, training all your other muscles similarly, and making sure all your muscles get the rest they need to build the muscle.