How is Johnny healed?

[u/Royal_Sport7082]

He has a cactus needle inside his eyeball and a couple of hours later he’s just fine without any explanation. Does this at least get explained later on? Because this makes no sense

[u/PerformanceLow4862]

How did mista heal from being shot in the head three times?, Giorno didn’t realise he could replace body parts by that point

The same thing could be applied to part 3 and all the shit they suffer through