okay first - she is a psychology student so she can start treating herself by studying different therapies

cognitive behavioral therapy is for depression
dialectic behavioral therapy is for borderline (MUST DO)
EMDR is for trauma but is not recommended but interesting to understand.

secondly she needs to start projecting herself outwardly in ways other than cutting. For example talking and getting out the thoughts that put her at risk and make her a danger to herself.

third she must seek comfort from her external environment. soft things, shiny things, food cravings, tea, bath salts, etcetera.