When I'm taking ghusl, 1) if wind passes from my back, will that invalidate my ghusl? Will I be able to perform salat with the ghusl? 2) if I start bleeding from a pimple, will that invalidate my ghusl?

In the name of Allāh, Most Gracious, Most Merciful  

Assalāmu ῾alaykum wa Rahmatullāhi Wabarakātuh

1) If a person performs ghusal and thereafter passes wind, his wudhu will be nullified not his ghusal. If he wishes to perform Salāh, he should renew his wudhu and perform his Salāh.

(Nūrul Idhāh, Pg.35, Qadīmi) ^[1]
 (Bahisti Zewar, Vol.1, Pg.54, Zam Zam)

2) If a pimple bursts and the blood flows out onto the skin, the wudhu will be nullified and not the ghusal. It will be permissible for you to perform your Salāh with that ghusal, however, you will have to renew the Wudhu.

(Nūrul Idhāh, Pg.35, Qadīmi) ^[2]
(Bahisti Zewar, Vol.1, Pg.54, Zam Zam)

3) If after performing Ghusal, any substance comes out from the rear, this will nullify the wudhu and not the ghusal. Only the wudhu will have to be renewed.

And Allāh Ta῾āla Knows Best

Checked and Approved by:
Mufti Ebrahim Desai
Dārul Iftāa