It is not unusual in a multi-car accident scenario that settlement can be held up for months, or longer. With multiple cars involved, there may be multiple people making an injury claim on the at-fault driver's policy limit. When there's a possibility that the policy limit is insufficient to pay everyone's injury claims, the adjuster will not make any settlement offers until all claimants are done treating and have submitted their settlement demands. The adjuster needs to see everyone's bills (medical bills and lost wages claims) and medical records before making any offers. Assuming the policy limit is insufficient to pay all claims, the adjuster will apportion the bodily injury policy limit, pro-rata, between the injury claimants.
If it turns out that the value of the combined claims does exceed the defendant's policy limit, if you have uninsured/underinsured motorist coverage under your policy, with a policy limit greater than the defendant's, you can make an underinsured motorist claim under your policy. Doing so will not affect your premiums whatsoever.
Hiring a lawyer after a multi-car accident will not necessarily get your case settled quicker. Whether you need a lawyer depends on the seriousness of your injuries. Our general advice: the more serious your injuries = the higher the value of your claim = the harder the insurance company will fight to hold onto their money = you likely should have an attorney fighting to get you everything you're entitled to. Our suggestion: run it by a personal injury law firm and get their opinion. Then you can decide whether you want to hire an attorney or not. Know that all personal injury lawyers provide free consultations.