now I did it! was shooting at a ghast in the nether , and a pigman got caught in the crossfire! now they are afer me! I stepped back through my portal and two of them followed me and killed me as I got to my home. when I respawned they were gone! now what do I do? will they still be here looking for me ? or did they return? are the ones in the nether waiting for me to return? will they remember me after awhile? man was it creepy being chased by so many! and what a sweet spot my portal is in, a small protected little hole in a cliff right near a stronghold and I saw a few blaze spawners across my bridge I started!!! hope I can go back!! HELP !!!
If you can get to your bridge and block it off behind you you should be able to finish it and get far enough away for them to forget about you, the Wiki seems to say more than 40 blocks away for more than 40 seconds.
Otherwise I've seen the suggestion of going to a spot in the overworld more than 2024 blocks from your original portal and building a new portal, going through it to the Nether (a safe distance away from the ZP) and walking back to the original portal in the Nether, thus making sure that the the chunks with the ZP are loaded and giving them time to forget you.
If you have locked your difficulty you can still change it, temporarily, by opening your game to LAN, you don't have to _have_ a LAN, just chose "Open to LAN" from the in game menu.
the two that followed me , did kill me , but in was in the over world. then when I respawned they were gone. so I waited a few cyles of day /night and poked my head down there, there were only two pigmen nearby but they walked right through a lava pol and fire to get o me , so they are not over it yet I will try that peaceful mode thing first see how it goes. would like to move the portal but I wan not too good at navigating the over world and the nether. would never be able to walk back to my old portal from a new portal from up here!
I'd say get a good enchanted diamond sword and some fresh armor (enchanted or not) and a bow with infinity or plenty of arrows, go through your portal and immediately build a platform up a couple blocks then try to kill all the pigmen within the area. You'll find that sooner or later you can clear out all the "locals" and once there's no local ones mad at you, any that respawn won't be mad either. We've gone to the nether and built towers and gotten the pigmen angry on purpose just to get XP, gold drops and well, because we're bored. Like I said, clear out all the mad ones and you'll be fine. Don't try to just stand and fight on level ground...Even with the best armor, the sheer numbers and the damage they do will kill you quick. If your portal is low enough in the nether and you have room to do it, you might be able to build a tower straight up to get 40+ blocks away and stay up there for a minute or two.
Direct from the wiki "Zombie pigmen will remain hostile for 20 to 39.95 seconds, although they will continue to pursue an already-targeted player after this time until the player dies or escapes their 40 block pursuit radius. Approaching an already hostile zombie pigman causes it to sound an alarm call, angering other zombie pigman in a 40-block radius. The forgiveness timer does not advance for zombie pigmen in unloaded chunks. Thus, if the player enters a Nether portal and returns, any provoked zombie pigmen in the area will still be aggressive unless another player was nearby to keep the chunks loaded. Dying will not cause zombie pigmen to become neutral towards the player, regardless of whether they killed you"
I went back down, the zombies that followed me initially respawned and came at me again, even though they killed me in the over world and got through the portal, but I killed them this time, they did not despawn back to the nether like last time. so I believe now I killed the original two that were angry with me. then a third one tried to sound and alarm but I think I killed him too quick, nobody showed up! . these guys walked though lava to get to me! where my portal is is easy for me to build a cobble wall and metal door to keep them away!