The first one we said:
Me han cortado el pelo (we don't know in this sentence who, but we know that it was someone else)
Me he cortado el pelo (I do it my self)
Verb: HACER (do)
Yo he
Tu/vos has
El/ Ella ha
Usted ha
Nosotr@s hemos
Vosotr@s habéis
Ustedes han
Ell@s han
We don't know who do it, thats why we use "HAN"
Other examples:
Él me ha cortado el pelo
Ella me ha cortado el pelo
Mi amigo me ha cortado el pelo
Me han cortado el pelo (SUJETO TÁCITO) (in Spanish the "sujeto táctico" means that we don't know WHO do it, obviously someone done it but we don't have "he, she, my friend" "él, ella, mi amigo" so we have a tacit subject)