Suspected overgrooming from other rat. No wounds , no pruritus, no fluorescence

小朱朱

Suspected overgrooming from other rat. No wounds , no pruritus, no fluorescence in Wood's lamp , and feels a bit damp/wet to touch, I suspect from other rat's saliva.  Ther have recently tried to introduce a third rat, after which grooming became intense.
After negative tape microscopy and comb test, owner did not want skin scrape or mycology or blood status sent.
So I tried gabapentin treatment of friend rat and owner will try to observe if it's overgrooming. Possibly split the rats if gaba won't help. I am a bit doubtful if gaba is the best choice though. (50mg/kg q24h). Anyone have other input?
(both rats are 2yrs old). Other rat no skin lesions.