Merz Pharma Group on Monday withdrew its $22-a-share offer for Obagi Medical Products Inc., leaving the Long Beach dermatology company with a sweetened offer by its original suitor, Valeant Pharmaceuticals International Inc. of Montreal.

Merz, of Frankfurt, Germany, had topped Valeant’s original offer of $19.75 a share for Obagi, prompting the Canadian company to boost its offer to $24 a share. Obagi signed its original merger agreement with Valeant last month, and its board last week approved an amended deal for the higher amount, which included a higher $21 million termination fee.

“Merz is a disciplined buyer, and at this level the economics of such a transaction do not meet our requirements,” Merz Chief Executive Philip Burchard said in a statement.

Valeant’s tender offer expires on April 23. Obagi makes skin care products that can be used after cosmetic surgery or to treat the signs of acne, aging and sun damage.

Obagi shares closed down $1.44, or 6 percent to $23.98 on the Nasdaq.