There isn’t really a good blessing for the end of baptism. I hope this might be useful to you:
May Christ, who marks you with his own cross
who washes you clean with the living waters of baptism,
who pours out his blessings on you in oil of chrism
who wraps you in his love
give you the light of new life in him
and the blessing of God almighty,
the +Father, the Son, and the Holy Spirit,
be among you and remain with you always.
Amen.
*This really answered my problem, thank you!