You can use below expression to fetch Custom Label in trigger

    String labelForDisease = Label.Label_for_Disease_Condition
    
    /*UserInfo.getUserId() will return the Id of the Current User executing the transaction*/
    
    Map<Id, User> userMap = new Map<Id, User>([SELECT Id, LHJ__c, Opted_In_To_Cross_Jurisdiction_Sharing__c FROM User WHERE Id = :UserInfo.getUserId()]);   
    
    /*UserInfo.getUserRoleId() returns the context user's role ID.*/
    
    **Map<Id, UserRole> userRoleMap = new Map<Id, UserRole>([SELECT Id, DeveloperName FROM UserRole WHERE Id = :UserInfo.getUserRoleId()]);**

Iterate on the `Trigger.New` List and use if blocks to check conditions and inside the if blocks you may use `addError('Error Message')` method to throw an error if the condition fails and the record will not update.

For Example:

```
trigger TriggerName on Object_Name__c (before insert, before update){    //Must be on Before Insert and before update events
    Map<Id, User> userMap = new Map<Id, User>([SELECT Id, LHJ__c, Opted_In_To_Cross_Jurisdiction_Sharing__c FROM User WHERE Id = :UserInfo.getUserId()]);
    Map<Id, UserRole> userRoleMap = new Map<Id, UserRole>([SELECT Id, DeveloperName FROM UserRole WHERE Id = :UserInfo.getUserRoleId()]);

    String labelForDisease =  = Label.Label_for_Disease_Condition;

    for(Object_Name__c rec: Trigger.New){
    
        if (!userMap.get(UserInfo.getUserId()).LHJ__c.contains(rec.CA_Local_Health_Jurisdiction__c)) {
             rec.addError('Validation error Message');
        }

        if (record.LR_Disease_Condition__c != labelForDisease) {
            rec.addError('LR Disease Condition is not correct');
        }
    }

}
```

Add more if blocks as per your validation rule.