All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon Prophet Mohammad and upon all his family and companions.
When making Tawaf for Hajj or Umrah, Kabaa should be on the left hand side of both the child and his guardian because this is among the conditions of valid Tawaf, as agreed by the majority of the Muslim scholars.
Al-Shbramalisi, a Shafie scholar, stated: "When a person makes Tawaf while holding his child, then the Kabaa should be on their left Hand side." {Nehayat al-Mohtaaj, vol.3/pp.82}.
Whoever failed to meet this condition should remake Tawaf, do Sai` between Safa and Marwa, then make Tahallul from Umrah {Release from state of Ihram}. However, if he returned to his country and it was difficult for him to go back to Makka, then, according to the Shafie doctrine, he and his child haven`t made at-tahallul al-akbar or at-tahallul ath-thani (Full release from Ihram), so he should go back and make Tawaf in the correct form. As for at-tahallul al-Asghar or at-tahallul al-awwal (Partial release from Ihram), it is valid and he isn`t bound by restrictions of Ihram save having sexual intercourse with wife. Yet, there is no sin in following the view of the Hanafie scholars who say that his tahallull and Hajj are complete, but he should slaughter a sheep and distribute its meat amongst the poor people of Makka. They added that his Hajj is valid and he doesn`t have to remake Tawaf. In fact, it is permissible for a Muslim who made a mistake to follow the view of some scholars to avoid hardship.
Ibn Nojayim {May Allah have mercy on him} said: "If Kabaa was on his right hand side during Tawaf, then his Tawaf is valid, but he incurred sin for leaving an obligation (Making Tawaf while Kabaa is on one`s left hand side). He should remake Tawaf so long as he is in Makka. But, if he left to his country, then he should slaughter a sheep and distribute its meat among the poor." {Al-Bahar Ar-Raa`iq}.
For further details about the Hanafie view on this topic, kindly refer to the Book "Al-Mabsoot, (vol.4/pp.44)" by Al-Sarkhasi". And Allah the Almighty knows best.