Firstly: 

It is permissible to pierce the ears in order to wear jewellery or other adornments. 

For more information please see the answer to question no. 78255 

Secondly: 

There is nothing wrong with piercing the ear more than once, because the basic principle is that it is permissible and there is nothing to indicate that it is not allowed. But that is on condition that it be in accordance with the traditions and customs of the people in your country. 

It says in al-Mawsoo‘ah al-Fiqhiyyah (29/216): The basic principle with regard to customs is that which was narrated from Ibn Mas‘ood (may Allah be pleased with him), who said: Whatever the Muslims regard as good is good before Allah. And in the books of usool al-fiqh there is that which indicates that traditions are to be taken into consideration with regard to fiqh. For example: 

The scholars said: “Customs are to regarded as rules… rather customs are to be taken into consideration if they become prevalent and well established. There is hardly any book of fiqh or any category of fiqh but you see custom playing a role in forming some of its rulings.

End quote. 

Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said: If a woman lives in a country where wearing jewellery in the nose is regarded as an adornment and beautification, then there is nothing wrong with piercing the nose in order to wear jewellery in it.

End quote from Majmoo‘ Fataawa Ibn ‘Uthaymeen, 11/ question no. 69 

He regarded it as permissible to pierce the nose in order to wear jewellery in it, if that is the custom of the women in one’s country. 

The same applies to piercing the ear more than once in order to wear jewellery. 

And Allah knows best.