It is said that eye is one of parts of your body which heals fastest, so usually people are back in their contacts again within a couple of weeks. And if the corneal abrasion is very little, your eyes would be healed in a day or two, and you can wear your contacts again after a few days later. But eyes are very sensitive organ, and corneal abrasion may cause other changes. So what I suggest is that you'd better go to see your ophthalmologist to make sure that your abrasion is totally healed before you wear your contacts again. And keep your hands and contacts clean to prevent any else eye problems.
For the sake of your eye healthy, you must let your eyes heal first. Besides, you shall be careful to avoid infections in during the time you for heal. Usually, it takes about a couple of weeks for most of people to cure a corneal abrasion. Anyway, you'd better get your eyes checked by an doctor. If the doctor told you that your eyes are cure and are able to wear contact lenses. You can do it.
After the corneal abrasion your eyes will be very weak. You'd better wait for your eyes become better then wear contacts.But the exact time depends on the integrity of the corneal epithelium, to see if it is suitable for wearing contact lenses. What's more, the lenses need to fit you well, you can go to the optician or hospital inspection to choose the right lenses.