Just Got My Nipple Pierced !!

Pe
Just got my nipple pierced and wanted to know anything and everything that I can. The piercer didn't exactly give me alot of information about the aftercare or nipple jewellery etc 
So I was wondering how long till I can change the jewellery ? (I know its meant to heal within 6-8 weeks)
Also with jewellery itself what is the recommended lengths and gauges?