Found a solution that worked based on a Biostar question, and a blasted bioinformatics blog post. Requires Blast+ 2.2.28 if your fasta doesnt follow NCBI naming exactly.
When you create the blast database, use the -parse_seqids
flag. Then with blastdbcmd, you can extract a range of the sequence
blastdbcmd -db t/blastTest/dmel -range 1-10 -entry some_seq_id