Lash retention is 50% your lash tech and 50% yourself. Any problems with your lashes after 48 hours is purely down to the aftercare.
Do not get your lashes wet for 24 hours.
Do not apply mascara or any products to your lashes.
Do not pick or touch your lashes.
Clean and brush your lashes.
Avoid heat directly on the lashes

Do not massage or firmly touch the area for 7 days after the procedure. This also includes facials.
Remain up right for at least 4 hours
No extreme heat (sunbed, steam room, saunas)
Do not do any strenuous activity/exercise for 24 hours.
Avoid alcohol or medication for blood thinning before the treatment as these could contribute to bruising.