When can I use perm lotion/hair dye/chemicals on my hair after hairline transplant?

Think about what your doctor may say if you follow someone else's advice and you end up with a bad result.The Internet may confuse you more with conflicting answers.  The only correct answer in your case is what your doctor (the one you paid a lot of money and trusted) recommends.  

I always recommend four to six weeks to wait before using any chemicals on your hair after a transplant.

We often dye the hair immediately before the transplant.  I would wait until the skin is well healed before you resume dyes.  7 to 10 days should be fine.  If the dye irritates the healed wound, stop dying for another week.  

After a hair transplant is compete and you give it enough time, you can use safe products on your hair 2 weeks after the procedure. Be careful of strong chemicals as they might cause damage to your exisiting hair.

You need to wait until you are completely healed in both recipient and donor areas.  It is usually safe to say around six weeks but each case is different as healing process is differnt inn each individual.