Is there any anti-mosquito lotions for a 7 month old baby?

Usually none. Other parents have used bounce fabric softener and citronella oil , just a tiny bit on the clothes and seems to work.Some stores sell those bug bands to ward off mosquito which you can try.
Yes-see below. The U.S. Centers for disease control states repellents made with deet or picardin offer the most protection against mosquitoes and ticks. Both are recommended for adults and kids 2 months of age & older. Picaridin is a chemical that's similar in effectiveness to deet, but it's odorless, lighter, and less irritating. Citronella-natural repellant needs frequent applications, and is not as effective.