Something is biting my two year old daughter at night?!

Something is biting my two year old daughter at night?

some mysterious creature is biting my daughter at night. she sleeps with me i am not getting bitten. when she wakes up she seems to have another bite. they are all on her back and neckline. i thought it was chigger bites at first but it seems like when she wakes up she has another bite. they start out as a small red bump that is very itchy. then it starts to get a clear liquid head on it. and then it finally scabs over. i have looked and looked for bed bugs. i dont see anything that would be a sign of them. i cleaned all the bedding. sprayed the bed down. vacuumed like crazy. i really dont know what they are. she had the exact same bites on her last year this time. and the doctor gave her anti itch cream. he wasnt sure if they were chigger bites or not. i am getting frustrated. i rent and i dont know if i should call the landlord and tell him i need someone to come and inspect because i cant find anything. what kid of bites do these sound like?

3 weeks ago
i just bought this mattress less than a year ago.... $400 . i would really have to hate to buy a new one. its a pillowtop so i cant flip it to the other side either.

my sister got these and as she got older they just went away